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Photographic 

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( 


I( 


THE 


ORE    DEPOSITS 


OF    THE 


UNITED  STATES  AND  CANADA. 


BY 


JAMES    FURMAN    KEMP,    A.B.,  E.M.. 

PROFESSOR  OF  GEOLOGY  IN  THE  SCHOOL  OF  MINES,  COLUMBIA  UNIVERSITY. 


THIRD  EDITION. 

ENTIRELY  REWRITTEN  AND  ENLARGED, 


NEW  YORK  AND  LONDON: 
THE  SCIENTIFIC  PUBLISHING  COMPANY, 

1900. 


20789 


'  a 


K21 


dr^^ 


1 

4 


COPTRiaHT,    1893  AND  1900, 
BY 

The  Scientific  Publishing  Company. 


■I 


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I 


1 


^jy 


ii 


PREFACE. 

The  following  pages  presuppose  for  their  apprehension 
Home  acquaintance  with  geologj'  and  mineralogy.  The  mate- 
rials for  them  bave  been  collected  and  arranged  in  connection 
with  lectures  on  economic  geology,  first  at  Cornell  University 
and  later  at  the  School  of  Mines,  Columbia  College,  To  the 
descriptions  of  others  the  author  has  endeavored  to  add,  as  far 
as  possible,  observations  made  by  himself  in  travel  during  the 
last  ten  years.  The  purpose  of  the  book  is  twofold,  and  this 
fact  has  been  conscientiously  kept  in  view.  It  is,  on  the  one 
hand,  intended  to  supply  a  condensed  account  of  the  metallifer- 
ous resources  of  the  country^  which  will  be  readable  and  serv- 
iceable as  a  text- book  and  work  of  reference.  For  this  rea- 
son every  effort  has  been  put  forth  to  make  the  bibliography 
complete,  so  that,  in  cases  where  fuller  accounts  of  a  region 
are  desired,  the  original  sources  may  be  made  available  in  any 
good  library.  But,  en  the  other  hand,  it  has  also  been  the 
hope  and  ambition  of  the  author  to  treat  the  subject  in  such  a 
way  as  to  stimulate  investigation  and  study  of  these  interesting 
phenomena.  If,  by  giving  an  extended  view  over  the  field,  and 
by  making  clear  what  our  best  workers  have  done  in  late  years 
toward  explaining  the  puzzling  yet  vastly  important  questions 
of  origin  and  formation,  some  encouragement  may  be  afforded 
those  in  a  position  to  observe  and  ponder,  the  second  aim  will 
1)6  fulfilled.  In  carrying  out  this  purpose,  the  best  work  of 
i-ecent  investigators  on  the  origin  and  changes  of  rocks,  espe- 
cially as  brought  out  by  microscopic  study,  has  been  kept  con- 
stantly in  mind,  and  likewise  in  the  artificial  production  of  the 
ove  and  gangue  minerals.  So  much  unsound  and  foolish  theo> 
rizing  has  been  uttered  and  believed  about  ores,  that  too  much 
care  cannot  be  exercised  in  basing  explanations  on  reasonable 
and  right  foundations. 


'W 


VI 


PREFACE, 


Acknowledgments  are  due  to  many  friends  for  encourage- 
ment, suggestion,  and  criticism.  To  Prof.  Henry  S.  Williams, 
now  of  Yale,  but  late  of  Cornell,  whose  interest  made  the  book 
possible,  these  are  especially  to  be  made.  On  particular  regions 
much  advice  has  been  obtained  from  Dr.  W.  P.  Jenney,  for 
which  the  author  is  grateful.  In  the  same  wa  Prof.  H.  A. 
Wheeler,  of  St.  Louis,  Prof.  R.  A.  F.  Penrose,  of  Chicago,  and 
several  other  friends  have  contributed.  Dr.  R.  W.  Raymond 
suggested  the  method  of  enumerating  the  paragraphs.  It  has 
the  advantages  of  being  elastic  and  of  showing  at  once  in  what 
part  of  the  book  any  paragraph  is  situated. 

The  geologists  of  the  United  States  Geological  Survey,  who 
have  been  engaged  in  the  study  of  our  great  mining  regions, 
especially  in  the  West,  have  laid  the  whole  scientific  world  un- 
der a  debt  of  gratitude,  and  in  this  country  have  probably  been 
the  most  potent  influences  toward  right  geological  conceptions 
regarding  ores.  Of  authors  abroad,  Von  Groddack  has  been  a 
means  of  inspiration  to  all  readers  of  German  who  have  inter- 
ested themselves  in  this  branch  of  geology.  The  writer  cannot 
well  forbear  acknowledging  their  influence. 

Should  errors  be  noted  by  any  reader,  the  writer  will  be  very 
appreciative  of  the  kindness  if  his  attention  is  called  to  them. 

J.  F.  Kemp. 

CoLUMBUN  College,  in  the  City  of  New  York,  1893. 


™ 


courage- 
Williams, 
the  book 
r  regions 
iney,  for 
f.  H.  A. 
ago,  and 
laymond 
It  has 
in  what 


rey,  who 
regions, 
'orld  un- 
bly  been 
iceptions 
IS  been  a 
ve  inter- 
ir  cannot 


PEEFACE  TO  THE  SECOND  EDITION, 

In  the  second  edition  many  pages  have  been  rewritten  and  ex- 
panded. The  endeavor  has  been  also  made  to  introduce  into 
the  body  of  the  work  the  new  materials  that  have  become  avail- 
able in  the  last  year.  •  This  is  especially  true  of  iron  ores,  of  the 
geology  of  the  Sierras,  and  of  nickel  and  cobalt.  In  all  some 
fifty  pages  of  new  matter  have  been  added,  and  fifteen  cuts. 
Acknowledgments  are  herewith  made  to  Professors  W.  H. 
Pettee,  of  Ann  Arbor;  H.  S.  Munroe,  of  New  York;  and  C.  H. 
Smyth,  Jr.,  of  Hamilton  College;  and  to  Mr.  now  Prof.  H.  L. 
Smyth,  of  Cambridge,  and  Prof.  W»  C.  Knight,  of  Laramie, 
for  suggestions,  as  requested  in  the  preface  to  the  first  edition. 

1895.  J.   F.   K, 


I  be  verj' 
to  them. 

Kemp. 


PEEFACE  TO  THE  THIED  EDITION.  . 

In  the  third  edition  the  title  has  been  expanded  so  as  to  in- 
clude Canada,  since  the  nature  of  the  contents  now  justifies  this 
change.  About  one  hundred  pages  of  new  matter  have  been 
added,  and  considerable  portions  of  the  former  text  have  been 
rewritten.  The  figures  have  been  doubled  in  number,  and 
many  maps  have  been  introduced.  The  writer's  thanks  are 
due  for  advice  and  assistance  to  Messrs.  W.  H.  Weed,  H.  W. 
Turner  and  John  D.  Irving,  of  the  United  States  Geological 
Survey,  to  Mr.  H.  F.  Bain,  of  the  Iowa  Geological  Survey,  to 
Mr.  S.  S.  Fowler,  of  Nelson,  B.  C,  and  to  many  of  his  students, 
now  in  the  active  practice  of  the  profession  of  mining  engi- 
neering. J.  F.  K. 

Decembke,  1899. 


m 


# 


TABLE  OF  C0NTT:NTS. 


PAOB 
I'UKFAOE V 

List  ob^  Illustrations xv 

List  of  Abbreviations xxi 

PART  I.— INTRODUCTORY. 

(Ff  AFTER  I.— General  Geulo<uc'al  Facts  and  Principles. 

The  two  standpoints  of  geology,  H,  4;  the  scheme  of  classifica- 
tion, 4,  o;  classification  of  rocks,  6;  brief  topograi)hical  survey  of 
tlve  United  States,  7,  8;  brief  geological  outline,  8-11;  forms  as- 
sumed by  rock  masses,  11,  13 1-12 

CHAPTER  II.— The  Formation  ot  Cavities  in  Rocks. 

Tension  joints,  13,  14;  cleavage,  fissility,  and  compression 
joints,  14-16;  by  more  extensive  movements,  10-21 ;  faults,  21-25; 
/ones  of  possible  fracture  in  the  earth's  crust,  25,  26;  secondary 
modifications  of  cavities,  26-;32 13-33 

CILVPTER  III.— The  Minerals  Important  as  Ores;  the  Gangue 
JIinerals,  and  the  Sources  whence  Bt)TH  are  Derived. 

The  minerals,  32;  source  of  the  metals,  32-38 32-38 

t'HAPTER  IV.— On  the  Filling  of  Mineral  Veins. 

Resume,  39;  methods  of  filling,  31),  40;  lateral  secretion,  40; 
ascension  by  infiltration,  40-44;  replacement,  44-46 39-46 

CHAPTER  v.— On  Certain  Structural  Features  of  Mineral 

Veins. 

Banded  structure,  47-49;  clay  selvage,  40;  pinches,  swells, 
'lateral  enrichments,  49,  50;  changes  in  character  of  vein  filling, 
r)0;  secondary  alteration  of  the  minerals  in  veins,  50-52;  electrical 
activity,  52,  53 47-53 

CHAl^TER  VI.— The  Classification  of  Ore  Deposits,  a  Review 
AND  A  Scheme  Based  on  Origin. 

Statement  of  principles,  54,  55;  principal  schemes,  55;  scheme 
entirely  based  on  origin,  55-59;  remarks  on  the  above,  and  dis- 
cussion of  methods  of  formation,  59-73;  fahlbands,  73;  phrase- 
ology used,  73 ;  character  of  the  rocks  containing  the  deposits, 
''■'>;  general  bibliography  of  ore  dejjosits,  74-79 54-97 


^ 


TABLE  OF  CdNTENTH. 


PART  II.— THE  ORE  DEPOHITS. 


PAnE 


CHAPTER  I.— TnK  IuonSkuikh  (in  PAm^.—lNTitouroToRY Remarks 
ON  Ikon  Okkh. — Limonite. — Sidekitk. 

Generul  literature,  83,  84;  table  of  analyses,  84;  general  re- 
marks on  coniixwition  and  ot'ourrfjuce,  85-87;  Linio'ute,  Exanij)le 
1,  boj(-or»<,  87-U2;  Example'^,  brown  heniatito  not  Hi  o-Cambrian, 
03-100;  Example  2a,  Siluro-Cainbrian  brown  licnialites,  100-104; 
origin  of  same,  104,  105;  analyses  of  linionites,  100;  siderito  or 
s]mthi()  ore,  introductory,  100;  Example  3,  clay  ironstone,  100, 
107;  Example  3r(,  black-band,  107-110;  Example  4,  Burden  Mines, 
110,  111;  Example  5,  Roxbuiy,  Conn.,  112;  genetic  discussion  of 
siderite,  112,  113 83-113 

CHAPTER  II.— The  Iron  Series,  Continued— Hematites,  Red  and 
Spkcular. 

Introductory  remarks,  114;  Example  0,  C'linton  ore,  114-121; 
Greenbrier  Co.,  VV.  Va.,  121;  MansHcld  ores,  rciiii.,  121,  152;  Ex- 
ample 7,  Crawford  Co.,  Mo.,  122,  12:!;  Example  8,  Jefferson  C'o., 
N.  Y.,  123-125;  f>xami)le  0,  Lake  Superior  bematites,  125;  intro- 
ductory, 12.5-121);  Manpiette  district,  120-130;  Menominee  dis- 
trict, 130-130;  Penokee-(TOgebic  district,  130-143;  Vermilion  Lake 
and  range,  144-1.50;  Jlesabi,  l.")0-154;  Example  10,  James  River, 
Va.,  154,  155;  Example  11,  Pilot  Knob,  Mo.,  15.5-157;  Example 
11a,  Iron  Mountain,  Mo.,  157,  158;  analyses  of  hematite.s,  150..  114-159 

CHAPI'ER  TIL— Magnetite  and  Pyhitk. 

Example  12,  Magnetite  beds,  KiO;  Adirondack  region,  100- 
160;  New  York  and  New  Jei*.sey  Higblands,  100-1 00;  South  Moun- 
tain, Penn.,  100;  Western  North  Carolina  and  Virginia,  100,  170; 
Colorado,  170,  171 ;  California,  171;  Example  13,  titauil'erous  mag- 
netites, 171-175;  Example  14,  Cornwall,  Pa.,  175-180;  Example  14a, 
Iron  Co.,  Utah,  180;  Example  15,  magnetite  sands,  180,  181;  origin 
of  magnetite  dejjosits,  181-183;  analyjsesof  magnetites,  183;pyrite, 
184-180;  Example  16,  pyrite  beds,  184-180;  statistics,  180;  remarks 
on  Cuban  and  Mexican  iron  ores,  18'J-188. 100-188 

CHAPTER  IV.— Copper. 

Table  of  analyses  of  copjier  ores,  189;  Example  10,  continued, 
pyrite  beds,  189-104;  Spenceville,  Cal,  195,  190;  Example  17, 
Bntte,  Mont.,  197-203;  CJilpin  Co.,  Colo.,  303,  204;  Llano  Co., 
Texas,  204;  Example  18,  Keweenaw  Point,  Mich.,  204-209;  origin 
of  the  copi^er,  209-212;  Example  19,  St.  Genevieve,  Mo.,  213,  214; 
Example  20,  Arizona  Copper,  214,  215;  Morenci,  215,  310;  classi- 
fication of  ores  by  Henrich,  316,  317;  Bisbee,  217,  218;  Globe,  218, 
319;  Santa  Rita,  N.  M.,  319;  Black  Range,  320;  Copper  Basin, 
220;  Crismon-Mammoth,  Utah,  231,  332;  Wyo.,  Idaho,  Wash., 
333;  Example  21,  copper  ores  in  Triassic  or  Permian  sandstone, 
322-224;  Eastern  States,  233,  224;  Western  States,  224;  statistics 
of  copper,  225 189-335 


TAliLK  OF  CONTENTS. 


Zi 

PAai 


CHAPTER  V  — T-KAn  Ar.oNE. 

IntHMluctoiy  Hiul  aualyHeH  of  lead  ores,  220;  Example  32,  At- 
luiitic  border.  Ht.  Lawrence  Co.,  N.  Y.,  220,  227;  ^Iuhs.,  Conn., 
and  Eastern  N.  Y.,  227;  Soutlioastern  Penn.,  227;  Davison  Co., 
N.  c;.,  228;  Sullivan  and  Ulster  Countif.M,  N.  Y.,  228;  Example 
23,  Houtlieastern  Misso\iri,  228-2iU  ;  statistics  of  lead,  232 226-283 

CHAPTER  VI  — Lkai)  and  Zino. 

Example  24,  Up|H>r  Miss.  Valley,  2!}3-237;  Washington  Co., 
Mo.,  2:{8,  2!}0;  LiviiiKston  Co.,  Ky.,  2!J9;  Example  2.'">,  Houthweat 
Missouri,  240-245;  Example  2(J,  Wythe  Co.,  Va.,  247-240 2iW-249 

CHAPTER  VII.— Zinc  Alo.ne.  oh  with  Mktals  otiikh  than  Lkad. 
Introduction:  Tables  of  analyses  of  zinc  ores,   2.">(>;  Example 
27,  Sancon  Valley,   Penn.,   2r)(),  2.')1;  Example  28.  Franklin  Fur- 
nace and  Sterlinjj;,  N.  J.,  2r(l-2.")7;  Zint;  in  the  Roc'cy  Mountains, 
258.  2."))) :  in  New  Mexico,  2r!» 250-259 

CHAPTKR  VIII.— Lkad  and  Siiaeu. 

Introiluction,  2(iO;  Rocky  Mountain  region  and  the  Black 
Hills,  -JliO,  274;  New  Mexico,  2{i()-2«2:  Example  2i),  Kelley  I>ode, 
2ti();  Lake  Valley,  2(5(l-2(}2;  Colora<lo,  2(r3-272;  Example  HO,  Lead- 
ville,  2t'>2-2(i(i;  Example  ;i(>ft,  Ten  Mile,  Summit  Co.,  2(U),  2(!7;  Ex- 
ample Mb,  Monarch  District,  Chau'eeCo.,  2()H;  Example  ;50c.  Eagle 
River,  Eagle  Co.,  2(58;  Example  Md,  Asjien,  Pitkin  Co.,  268-271; 
Example ;JOc,  Rico,  Dolores  Co.,  271,  272;  Example  31,  Red  Moun- 
tain, Ouray  Co.,  272;  South  Dakota,  Example  30/,  272;  Jlontana- 
Idaho,  Example  32,  Glendale,  273;  Example  32a,  Wood  River,  273; 
Example  33,  Wickes,  Jefferson  Co.,  273;  Example  34,  Coeur 
d'xVlene.  274;  Region  of  tiie  (ireat  Basin,  274-270;  Utah,  Exam- 
ple 3."),  Bingham  and  Big  iiud  Little  Cottonwood  Caflons,  274,  275 ; 
Example  35a,  Tooele  Co,,  275;  Example  356.  Tiutio  District, 
27."»;  Example  30(/,  Hornsilver  Mine,  275,  276;  Example  33a,  Car- 
bonate Mine,  Beaver  Co.,  270;  Example  32&,  Cave  Mine,  Beaver 
Co.,  276;  Nevada,  Ex.ample  20,  Eureka,  377,  378;  Arizona;  Cali- 
fornia, 279 260-279 

CHAPTER  IX.  —Silver  and  Gold.  — Introductory:  Eastern 
Silver  Mines  and  the  Rocky  Mountain  Region  of  New  Mex- 
ico AND  Colorado. 

Introduction,  280;  Examples  37-42,  defined,  280,  281;  silver 
and  gold  ores,  281-283;  Example  22a,  Atlantic  Border,  283;  Ex- 
ample 42,  Silver  Islet,  Lake  Sui)erior,  283,  284;  Thunder  Bay, 
Canada,  284;  region  of  the  Rocky  Mountains  and  the  Black  Hills, 
284-307;  New  Mexico,  geology,  284,  285;  mines,  285,  286;  Colorado, 
geology,  286,  287;  S;,n  Juan  region,  287-293;  Creede  region,  203; 
Gunnison  region,  204;  Eagle  Co.,  204;  Summit  Co.,  294,  205; 
Park.  Chaffee,  Rio  Grande  Counties,  205;  Conejos  Co..  200;  Cus 
ter  Co.,  200;  Example  39,  Bassick  Mine,  290,  207;  Example  30a. 


w 


Xll 


TABLE  OF  CONTENTS. 


PAGE 

Bull  Domingo  Mine,  297-309;  Humboldt-Pocahontas,  299;  Silver 
Cliff,  299,  300;  Teller  Co.,  300-305;  Gilpin  Co.,  305,  300;  Clesir 
Creek  Co.,  30C;  Boulder  Co.,  306,  807 280-307 

CHAPTER  X. — Silver  and  Gold,  Continued.— Rocky  Mountain 
Reuion,  Wyoming,  the  Black  Hills,  Montana,  and  Idaho. 

Wyoming,  geology,  308;  South  Dakota,  geology,  309;  the 
Black  Hills,  309-314;  Montana,  geology,  314-310;  Madison  Co., 
316,  317;  Beaverhead  Co.,  317;  Jefferson  Co.,  317,  318;  Silver 
Bow  Co.,  318,  319;  Broadwater  Co.,  819;  Deer  Lodge  Co.,  319; 
Lewis  and  Clarke  Counties,  320;  Meagher  Co.,  320,321;  Ca.scade 
Co.,  321;  Flathead,  Choteau,  and  Fergus  Counties,  322,  323; 
Idaho,  geology,  323;  Kootenai  and  Lemhi  Counties,  324;  Custer, 
Boise,  Alturas,  and  other  counties,  324-327 308-327 

CHAPTER  XI.— Silver  and  Gold,  Continued.— The  Region  of  the 
Great  Basin,  in  Utah,  Arizona,  and  Nevala. 

Utah,  geology,  328;  Ontario  and  otlier  iiiines,  329,  330;  Ex- 
ample 41,  Silver  Reef,  333,  334;  Arizona,  geology,  334;  Ai)aclie, 
Yavapai,    Mohave,    Yuma,    Maricopa,    and  Pinal   Counties,   335; 

'  Silver  King  mine,  335,  330;  (>raham  and  Cochi.se  Counties,  330; 
Tombstone,  33();  Pima  and  Yiuua  Counties,  336.  337;  Nevada, 
geology,  337;  Lincoln,  Ney,  and  White  Pine  Counties.  338,  339; 
Liinder  and  other  counties,  339,  340;  the  Comstock  Lode,  340- 
345 328-340 

CHAPTER  XII  —The  Pacific  Slope— Washington,  Oregon  and 
California. 

Washington,  geologj%  346;  mines,  347;  Oregon  geology,  347, 
348;  Example  44a,  Port  Orford,  348,  349;  California,  geology,  349, 
350;  Calico  District,  351-353;  E.vample  44,  auriferous  gravels, 
353-302;  river  gravels,  353,  354;  high  or  deep  gravels,  354-300; 
general  resiune  of  geological  history  of  gravels,  300-362 ;  Example 
'5,  gold-quartz  veins,  302-375 346-87r) 

CHAPTER  XIII.- Gold  Elsewhere  in  the  United  States  and 
Canada. 

Example  45o,  Southern  Appalachians,  376-378;  Alabama,  378, 
379 ;  Georgia,  379 ;  South  Carolina,  380 ;  North  Carolina,  380,  381 ; 
Virginia,  Maryland  and  the  Nortliern  Stiites,  381-383;  Example 
456,  Ishpeming,  Mich.,  383,  the  Rainy  River  District,  383-385; 
Alaska  and  the  Canadian  Nortlnvest,  geology,  38.5-389 ;  Example 
38,  Douglass  Island,  390-393 ;  Yukon  Basin,  393-397 ;  Examjjle  45c, 
Nova  Scotia,  397-399;  gold  e'sc where  in  Canada,  400,  401;  sta- 
tistics, 401,  402 376-40J 

CHAPTER  XIV.— The  Lesser  Metals— Aluminum,  Antimony,  Ar- 
senic, Bismuth,  Chromium,  IManganese. 

Aluminum,  403-410;  antimonj^  410,  411;  Example  47,  includ- 
ing California,  Nevada,  Arkansas,  New  Bnmswick.  410,  411;  Ex- 


4 


I 


'■^ 


2\iBLE  OF  CONTENTS. 


PAOIC 

);  Silver 
5 ;  Cletir 
280-307 

OUNTAIN 
DAHO. 
300;  the 
son  Co., 

;  Silver 
Co.,  319; 

Cascade 
i23,  323; 
;  Custer, 

308-327 

N  OF  THE 

330;  Ex- 
Ai)ache, 
ies,  335 ; 
;ies,  33(5; 
Nevada, 
338,  339; 
ide,  340- 
328-34.1 

JON  AND 

ogy,  347, 
ogy,  349, 

gravels, 

354-300; 
Example 

346-37r. 

TES   AND 

una,  378, 
380,  381; 
Example 

383-385; 
Example 
nple  45c, 
401;  sta- 

376-40i 

)NY,  AR- 


XllI 


PAGE 


ample  4«,  Iron  Co.,  Utah,  411;  arsenic,  412;  bi.smuth,  412-  chro-' 
mnnn,  415,  416;    Example  49.  chromite  in  serpentine    414  415  • 
California,   415,   410;    Quebec,   416;   mangano.se.  416-423-   Exam' 
l)le  50,  manganese  ores  in  residual  clay,  418-423;  Batesville  Ark 
420-422 ;  Panama,  423 403-423 

CHAPTER   XV.- The    Lesser    Metals.    Continued.-Mercury 
Nickel  and  Cobalt,  Platinum,  Tin.  ' 

Mercury,  ores.  424,  425;  Example  50,  New  Almaden,  425  426- 
Example  50a,  Sulphur  Bank,  427;  Example  .W>,  Steam'  3at 
Springs,  Nov.,  427;  resume  regarding  mercuiy,  428;  nickel  and 
cobalt,  428-441;  introductory,  428-430;  Example  10c,  pyrrhotite 
beds  or  veins,  430,  431 ;  Example  13a,  (iap  mine,  Penn.,  Sudbury 
Ont.,  431-438;  Example  49a.  Riddle's,  Oregon,  438-440;  Example 
ma,  Mme  la  Motte,  Mo..  440;  other  occurrences  of  nickel  ores 
440,  44i;  platinum,  441;  tin,  441,  442;  Example  51.  Black  Hills' 
442,  443;  other  occurrences  of  tin,  443,  444;  Mexico,  444 424-444 

CHAPTER  XVI. -Concluding  Remarks. 

Summation  of  such  general  geological  relations  among  North 
American  ore  deposits  as  can  be  detected 44,5-447 

APPENDIX  I.— A  Review  of  the  Schemes  for  the  Classification 
01'' Ore  Deposits. 

General  remarks,  447,  448 ;  scliemes  involving  only  the  classification 
of  veins,  448-451 ;  general  scliemes  based  on  forms,  451-453;  schemes 
partly  ba.sed  on  form,    partly   on  origin.    4.53-455;  schemes  largely 
based  on  origin,  4,55-457;  schemes  entirely  based  on  origin,  457-4.59  ■ 
remarks  on  schemes  and  classification  of  ore  deposits,  459-462. .  .447-462 


',  includ- 
411;  Ex- 


FIOS. 

1.  lU 

2.  Oj 


3.  N( 

4.  Re 

5.  Ill 

6.  Ba 

7.  Me 

8.  Cr 

] 

9.  Se( 


10.  Vi( 

i 

11.  Gei 

( 

13.  Ide 

] 

Vi.  Ge( 
1 

14.  Vie 

I 

15.  Ma] 

i 
Hi.  Clii 
IT.  Clii 
l''^.  Clir 


LIST  OF  ILLUSTKATIONS 


FIOS. 

1.  lUustration  of  rifting  in  granite  at  Cape  Ann,  Mass.    After  R  S  "'"' 

Tarr .....,.....'     13 

2.  Open  fissure  in  the  Aubrey  limestone  (Upper  Carboniferous),  25 

miles  north  of  Cailon  Diablo  Station,  on  the  A.  &  f.  R.R., 
Arizona.     Photographed  by  G.  K.  Gilbert,  1»92 .Opp!     20 

3.  Normal  fault  at  Leadville,  Colo.     After  A.  A.  Blow  20 

4.  Reversed  fault  at  Holly  Creek,  near  Dalton,  Ga.     After  C.  W. 

Hayes '       "     g^ 

5.  Illustration  of  an  older  vein,  the  Jumbo  faulted  by  a  later  one 

(cross  vein)  at  Newman  Hill,  Rico,  Colo.     After  T.  A.  Riekard.    24 

6.  Banded  vein  at  Newman  Hill,  near  Rico,    Colo.     After  J.   B. 

Farisli '     „„ 

7.  Map  showing  the  distribution  of  iron  ores  in  North  America 88 

8.  Cross-section  of  the  Prosser  iron  mine  near  Portland,  Ore.,  show- 

ing the  bed  of  limonite  between  two  flows  of  basalt  '  After 
B.T.Putnam , gj 

9.  Section  of  the  Hurst  limonite  bank,  Wythe  Co.,  Va.,  illustrating 

the  replacement  of  shattered  limestone  with  limonite  and  the 
formation  of  geodes  of  ore.     After  E.  R.  Benton 93 

10.  View  of  the  Low  Moor  limonite  mines,  Virginia.  After  a  photo- 
graph by  J.  F.Kemp Opp.     95 

U.  Geological  section  of  the  Low  Moor,  Va.,  iron  ore  bed.     After  B. 

S.Lyman '     gg 

13.  Ideal  cross-section  of  Iron  Hill  near  Waukon,  Allamakee  Co 

I"«a '    99 

i:i.  Geological  section  of  the  Amenia  mine,  Dutohess  Co.,  N.  y! 

After  B.  T.  Putnam '  "  jqq 

14,  View  of  the  Siluro-Cambrian,  brown  hematite  bank  at  Baker 

Hill.  Ala.     From  the  Engineering  and  Mining  Journal.  . . Opp.  108 
I  1   Map  and  sections  of  the  Burden  spathic  ore  mines.     After  J.  P. 

Kimball 1 1  n 

16.  Clinton  ore,  Ontario,  Wayne  Co.,  x\.  Y.     After  C.H.  Smyth   Jr  115 

17.  Clinton  ore,  Clinton,  N.  Y.     After  C.  H.  Smyth,  Jr 116 

18.  Clinton  ore.  Eureka  mine,  Oxmoor,  Ala.     After  C.  H.  Smyth,  Jr.  117 


XVI 


LliST  OF  ILLUHTRATIONS. 


FIG.  PAOK 

19.  Cross-section  of  the  Sloss  mine.  Red  Mountain,  Ala.     From  the 

Engineering  and  Mining  Journal 117 

30.  Map  of  the  vicinity  of  Birmingham,  Ala.  From  tlie  Transac- 
tions of  the  Atnerican  Institute  of  Mining  Engi)ieers 119 

21.  "View  of  Clierry  Valley  mine,  showing  sandstone  with  underly- 
ing cherty  clay.     After  F.  L.  Nason 0pp.  12'2 

23.  Section  of  the  northern  end  of  the  Cherry  Valley  mine.     After 

F.  L.  Nason 0pp.  123 

23.  Cross-section  of  the  Cherry  Valley  mine.     After  F.  L.  Nason.  0pp.  122 

24.  Map  of  the  Lake  Sui)erior  region,  sliow  ing  tlie  location  of  the 

iron-ore  districts.     From  U.  S.  Geological  Survey 12(5 

25.  Generalized  section  across  Marquette  iron  range,  to  illustrate  the 

type  of  folds.     After  C.  R.  Van  Hise 129 

26.  Geological  map  of  the  western  portion  of  the  Marquette  iron 

range.     After  Van  Hise  and  Bayley 130 

27.  Geological  map  of  the  eastern    portion  of  the  Marquette  iron 

range.     After  Van  Hise  and  Bayley 131 

28.  Cross-section  to  illustrate  the  occurrence  and  associations  of  iron 

ore  in  the  Marquette  district,  Michigan.     After  C.  R.  Van 
Hise 133 

29.  Open  cut  in  the   Rejmblic  mine,  Marquette  range,  showing  a 

horse  of  jasper.     After  H.  A.  Wlieeler Opp.  133 

30.  Plan  of  the  Ludington  ore  body,  Menominee  district,  Michigan. 

After  P.  Larsson 137 

31.  Geological  map  of  the  Penokee-Gogebic  iron  range.    After  Irving 

and  Van  Hise 140 

32.  Longitudinal  and  cross-section  of  the  Ashland  mine,  Ironwood, 

Mich.,  re-drawn  from  mine  maps 142 

83.  Cross-section  of  the  Colby  mine,  Penokee-Gogebic  district.  Michi- 
gan, to  illusti"ate  oocurrence  and  origin  of  tlie  ore.  After  C. 
R.  Van  Hise 143 

34.  Map  of  the  Minnesota  ii"on  ranges.     After  F.  W.  Denton 145 

35.  Geological  map  of   tlie   vicinity  of  Tower  and  Soudan,  Minn. 

After  Smyth  and  Finlay 147 

36.  Cross-sections  of  the  oi'e  bodies  at  Soudan,  Vermilion  Range, 

Minn.     After  Smyth  and  Finlay 149 

37.  Ojien  cut  at  Minnesotii  Iron  Co.'s  mine,  Soudan,  near  Tower,  in 

south  vein,  looking  west.     After  J.  F.  Kemp Opp.  148 

88.  Horizontal  and  vertical  cross-section  of  the  Cliandler  ore  body  at 

Ely,  Minn.     After  Smyth  and  Finlay 150 

39.  View  of  Chandler  mine,  showing  sinking  of  ground.     After  J.  F. 

Kemp Opp.  119 

40    General  cross-section  of  ore  body  at  Biwabik,  Mesabi  Range, 

Minn.     After  H.  V.  VVinchell IM 

41.  View  of  the  Mesabi  Mountain  or  OHver  mine,  Virginia,  Minn., 

looking  .southeast.     After  J.  F.  Kemp Opp.   1")3 

42.  Cross-section  of  Pilot  Knob,  Mo.    From  drawing  by  W.  B.  Potter  156 


LIST  OF  ILL  U8TRA  TIONS. 


xvil 


PAGE 

rom  the 

117 

"/•aHsac- 

119 

juderly- 
...0pp.  12-3 
,     After 
...Opp.  12.2 
on.O])p.  122 
1  of  the 

121) 

;rate  the 

12!) 

itte  iron 

lliO 

itte  iron 

131 

8  of  iron 
R.  Van 

I3;i 

owing  a 
....Opp.  133 
[ichigan. 

137 

3r  Irving 

14(1 

on  wood, 

u-i 

t.  IMichi- 
After  C. 
1-13 

145 

11,  Minn. 
117 

Range, 

14!i 

ower,  in 
....Opp.   11^ 
!  body  at 

\m 

'ter  J.  F. 

..Opp.  Hit 

Range, 

IM 

I,  Minn., 
....  Opp.    1  "lo 
i.  Potter  I'jO 


via.  P'*"'' 

43.  View  of  oix;n  cut  at  Pilot  Knob,  Mo.,  allowing  the  bedded  char- 

acter of  the  iron  ore.     After  J.  F.  Kemp Opp.  157 

44.  View  of  Iron    Mountain,    Mo.,    from   the   east.     After  H.   A. 

Wheeler Opp.  158 

4r).  Cross-section  of  Iron  Mountain,  Mo.     By  W.  B.  Potter 156 

46.  View  oi'  open  cut  and  underground  work  in  mine  21,  Mineville, 

near  Port  Henry,  N.  Y.     After  J.  F.  Kemp Opp.  163 

47.  Cross  section  of  the  Cheever  iron  mine,  near  Port  Henry,  N.  Y. 

After  J.  F.  Kemp 163 

48.  Geological  map  of  the  iron  mines  at  Mineville,  near  Port  Henry, 

N.  Y.     After  J.  F.  Kemi) 163 

49.  Cross-section  of  ore-bodies  at  Mineville,  near  Port  Henry,  N.  Y., 

to  accompany  map.  Fig.  48.     After  J.  F.  Kemp 164 

m  and  51.  Jlodel  of  the  Tilly  Foster  ore  body.     After  F.  S.   Rutt- 

mann  and  J.  F.  Keni]) 166 

.")2.  Sketcli  map  illustrating  tlie  geological  structure  of  the  Hihernia 

magnetite  beds,  Hiljaniia,  N.  J.     After  J.  E.  Wolff 168 

.")3.  Section  along  Cornwall  Railroad  from  Lebanon  to  Jliner's  Vil- 
lage.    After  E.  V.  d  Invilliers 176 

")4.  ]\Iap  of  Cornwall  mines.     After  E.  V.  dlnvilliers 177 

.'),■).  Map  of  Ducktown,  Tenn.,  copper  mines,  .showing  the  relations 

and  extent  of  the  veins.     After  Carl  Henrich 191 

50.  Cross-section,    shaft  3,    Old  Tennes.see  mine,   Ducktown,  lenn. 

After  Carl  Henrich 193 

57.  View  of  the  Mary  Mine,  Ducktown,  Tenn.,  from  the  west.    From 

a  pliotograph  by  J.  F.  Kemp Opp.  194 

58.  Geological  map  of  the  we.stern  lialf  of  Butte  district,  Montana, 

reproduced  from  map  of  U.  8.  Geological  Survey 198 

59.  Geological  map,  eastern  half,  Butte  district,  Montana.    Idem....  199 

60.  View  of  the  Big  Butte.  Butte  City,  Mont.,   looking  northwest 

across  Mis.«oula  (4ulcli.  From  photograph  by  J.  F.  Kemp.. Opp.  200 

01.  View  of  the  Anaconda  mine,  Butte,  Mont.    From  photograph  by 

Alexander  Brown Opp.  200 

02.  View  of  the  larger  cojjper  mines,  Butte,  Mont.,  looking  nearly 

due  east  from  the  roof  of  the  Hotel  Butte.     From  photograph 
by  J.  F.  Kemp Ojip.  201 

03.  Contact  of  the  older  Butte  granite  and  the  later  intruded  Blue- 

bird granite  as  exposed   in  a  cut  on  the   Butte,  Anaconda, 
Pacitic  R.  R.     Photographed  by  J.  F.  Kemp Opp.  203 

04.  Cross  section  of  the  Bob-tail  mines.  Centra!  Cit\-,  Colo.     After  F. 

M.  Endlich ' 204 

05.  Geological  section  of  Keweenaw  Point,  Mich. ,  near  Portage  Lake 

and  through  Calumet.     After  R.  D.  Irving 206 

00.  Map  of  the  I'ortage  Lake  district,  Keweenaw  Point,  Mich 207 

67.  Cross-section  in  the  St.  Genevieve  copper  mine,  illustrating  the 

relations  of  the  ore.     After  F.  Nicholson 213 

08   Section  at  the  St.  Genevieve  mine,  illustrating  the  intimate  re- 
lations of  ore  and  chert.     After  F.  Nicholson 213 


xvin 


LIST  OF  ILLUSTRATIONS. 


PIO.  PAOK 

69.  Geological  map  of  the  Morenci  or  Clifton  copper  district  of 

Arizona.     After  A.  F.  Wendt 214 

70.  Vertical   section   of  Longfellow  Hill,  Clifton  district,  Arizona. 

After  A.  F.  Wendt 21.-) 

71.  Horizontal  .section  of  Longfellow  ore  body.     After  A.  F.  Wendt.  21.") 

72.  Geological  section  of  the  Metcalf  mine,  Clifton  district,  Arizona. 

After  A.  F.  Wendt 21() 

73.  View  of  the  Cop[)er  Queen  mine,  Bisbee  district,  Arizona.     From 

photograph  by  James  Douglass OpP'  2ls 

74.  Cross-section  of  the  Schuyler  copper  mine.  New  Jersey.     After 

N.  H.  Darton 223 

75.  Geological  map  of  the  Southeastern  IMissouri  disseminated  lead 

ore  sub  district.     After  Arthur  Wiuslow 22!) 

76.  Gash  veins,  fresh  and  disintegrated.     After  T.  C.  Chamberlin . .  23 1 

77.  Idealized  section  of  "flats  and  pitches,"  forms  of  ore  bodies  in 

Wisconsin.     After  T.  C.  Chamberlin 23.^) 

78.  Chart  showing  the  results  of  deep  borings  in  the  Joplin  district, 

]\Io.     From  Engineering  and  Mining  Journal 241 

79.  Vertical   section   of  a  tyi)ical  zincblende  ore  body,  near  Webb 

City,  Mo.     After  C.  Henrich 243 

80.  Geological  section  of  the   Bertha  zinc  mine.  Wythe  Co.,  Va. 

After  W.  H.  Case 24() 

81.  Geological  section,  Altoona  coal  mines  to   Bertha  zinc  mines. 

After  W.  H.  Case 248 

82.  View  of  o\^a\  cut  in  Bertha  zinc  mine,  Va,     Photographed  by  J. 

F.  Kemp 0pp.  248 

83.  View  of  open  cut  in  the  Wythe  zinc  mines,  Va.     Photographed 

by  J.  F.  Kemp Opp.  248 

84.  Cross-section  at  Franklin  Furnace,  N.  J.,  corresponding  to  A  A, 

of  map  (Fig.  88).     At  tlie  left  is  blue  limestone  and  quartzite. 
After  J.  F.  Kemp 2r)-3 

85.  View  of  the  west  vein  at  Franklin  Furnace,  looking  south.     The 

two  shafts  are  at  the  Ti-otter  mine.     Photographed  by  J.  F. 
Kemp 0})ii.  i'vl 

86.  View  of  the  open  cut  at  south  end  of  Mine  Hill,  Franklin  Fur- 

nace, N.  J.,  exposing  the  syncline  of  ore.     Photographed  by 
J.  F.  Kemp Opji.  2r)3 

87.  View  of  Sterling  Hill,  Ogdensburgh,  N.  J.     From  photograph  by 

J.  F.  Kemp Opp.  2.")3 

88  and  8!).  (Geological  map  of  Mine  Hill  and  Sterling  Hill,  showing 

the  relations  of  the  ore  bodies.     After  J.  F.  Kemp 255 

90  and  01.  Stereograms  of  the  ore  bodies  at  Mine  Hill  and  Sterling 

Hill.     After  J.  F.  Kemp 25r) 

92.  Geological  cross  section  at  Lake  Valley,  New  Mexico,  to  show 

the  relations  of  the  ore.     After  Ellis  Clark 261 

83.  Section  of  the  White  Cap  chute,  Leadville,  showing  the  geo- 
logical relations  of  the  ore,  and  its  passtige  into  unchanged 
sulphides  in  depth.     After  A.  A.  Blow 264 


T 


FIO. 


PMIK 

94. 

rict  of 

214 

95. 

rizona. 

"I.'i 

96 

A'endt.  2ir, 

rizona. 

97. 

21(5 

From 

..0pp.  318 

98 

After 

223 

99. 

3d  lead 

00() 

100. 

erlin . .  234 

dies  in 

101. 

235 

102. 

istriet, 

241 

103. 

Webb 

243           j 

104. 

3.,  Va.                   ; 

24()           ; 

105. 

mines. 

24S 

106. 

I  by  J. 

..0pp.  248 

107. 

raphed 

..Opp.  248 

108. 

;o  AA, 

irtzite                   i 

109. 

2o->            ' 

.     The 

110 

'  J.  F. 

.  .Oi)p.  '■')] 

111. 

n  Fur- 

led hy 

112. 

..0pp.  253           ■:\ 

iph  by                    " 

113. 

,.Oi)p.  253 

114. 

owing 

255 

115. 

;erling 

25(5 

116. 

sllQW 

261 

117. 

3  geo-                 ; 

auged                   ' 

264 

LIST  OF  ILLUSTRATIONS.  xix 

PAOB 

Section  through  the  No.  2  ore  chute  of  the  Robinson  mine,  Ten- 
mile  district,  Colo.     After  S.  F.  Emmons 267 

Cross-.section,  Queen  of  the  West  mine.  Ten-mile  district,  Colo. 
After  S.  F.  Emmons 367 

Geological  section  at  the  Eagle  River  mines,  Colo.  After  E.  E. 
Olcott 269 

A — Cross-section  of  the  Delia  S.  mine.  Smuggler  Mt. ,  Aspen, 
Colo.     After  J.  E.  Spurr 270 

B — Section  through  the  Durant  and  Asiien  mines.  ByD.  Rohlfing  270 

View  of  the  Bunker  Hill  and  Sullivan  mines,  Wardner,  Idaho. 
Photographed  by  E.  E.  Olcott Opp.  274 

View  of  town  of  Mammoth,  Tintic  district,  Utah.  Photographed 
by  I..  E.  Riter,  Jr Opp.  275 

Bullion  and  Beck  mine  and  mill,  Eureka,  Tintic  district,  Ut<ih. 
Photographed  by  L.  E.  Riter,  Jr Opp.  275 

Section  at  Eureka,  Nev.     After  a  plate  by  J.  S.  Curtis 278 

Geological  sketch  map  of  the  Telluride  district,  Colo.  After 
Arthur  Winslow 289 

Geological  cross-.sections  of  strata  and  veins  at  Newman  Hill, 
near  Rico,  Colo.     After  J.  B.  Farish 291 

Geological  cross-sections  of  strata  and  veins  at  Newman  Hill, 
near  Rico,  Colo.     After  J.  B.  Parish 292 

Cross-section  of  the  Bassick  mine,  near  Rosita.  After  S.  F. 
Emmons 298 

Cross  section  of  the  Bull-Domingo  mine,  near  Silver  Cliff,  Colo. 
After  S.  F.  Emmons 298 

Cross-section  of  the  Humboldt-Pocahontas  vein,  near  Rosita, 
Colo.     After  S.  F.  Emmons 299 

Geologitial  map  of  Cripple  Creek,  Colo.  U.  S.  Geological  Survey. 
(ieology  by  Cross  and  Matthews 301 

View  of  Crijjple  Creek,  Colo.,  from  Mineral  H.U;  Gold  Hill  in 
background.     Photographed  by  J.  F.  Kemp Opp.  303 

View  of  Battle  Mt.,  Victor,  Colo.,  Portland  group  of  mines  and 
Independence  mine.     Photograi)hed  by  J.  F.  Kemp Opp.  302 

Map  of  the  Independence  and  Washington  claims.  Cripple  Creek, 
Colo.     After  R.  A.  F.  Penrose 303 

Stereogram  of  the  Annie  Lee  ore-chute,  Victor,  Colo.  Aft^r  R. 
A.  F.  Penrose 304 

Geological  section  of  the  Black  Hills.      After  Henry  Newton ....  309 

Geological  section  of  the  strata  in  the  Northern  Black  Hills, 
S.  D.     After  John  D.  Irving 310 

Plan  and  ciosssection  of  the  Cambrian,  siliceous  gold-ore  de- 
posits in  the  Black  Hills,  S.  D.     After  John  D.  Irving 311 

Plan  and  section,  Mail  and  Express  mine,  to  illustrate  the  sili- 
ceous gold  ores  of  the  Black  Hills,  S.  D.  After  John  D.  Irving.  313 

View  of  Green  Mt.,  Black  Hills,  S.  D.,  a  laccolite  of  phonolite, 


r 


tt 


f' ! 


XX 


LIST  OF  lLLUt<TIiATlON8. 


FIO.  PAOE 

with  the  mines  of  siliceous  ore  on  the  so-called  "ui)i)er  con- 
tiict,  "  around  the  foot.   Pliotoj^raplied  liy  John  1).  Irviiif^.   Opp.  312 
lib.  View  of  the  L'nion  iiiim*  in   siliwuus    ore,   near  Terry,   Black 

Hills,  S.  T).     I'iioto^'niplied  hy  Joiin  D.  Irving Opp.  312 

119.  Cro.ss-sectioii  of  a  siliceous  gold  ore  hody  lying  next  to  a  porphyry 

dike,  Black  Hills,  S.  D.     After  John  D.  Irving 313 

120.  Prospective  (n'oss-section  of  'dliceous  gold  ore-body,  in  Carbonif- 

erous limestone,  Dacy  Flat    Black  Hills,  S.  D.     After  Jolin  D. 
Irving Opp.  31:5 

121.  View  of  the  Golden  Star  open  cut,  Lead  City,  S.  D.     Photo- 

graphed by  J.  F.  Kemp Opp.  31:! 

122.  View  of  the  outcrop  of  the  Wabash  silver  lode  projecting  above 

the  granite.  Butte.  Jlont.    Photographed  by  A.  C.  Beatty .  .Opp.  318 

123.  View  of  weathered  granite,  Butte,  Mont.     Photographed  by  J. 

F.  Kemp Opp.  31S 

124.  Cross-section  of  vein  of  the  Alice  mine,  Butte,  Mont.     After  W. 

P.  Blake 31H 

125.  The  old  gold  diggings  on  Napias  Creek,  Leesburg,  Idaho.     Illus- 

trating  an  abandoned  placer  camp.     Photograi)hed  by  J.  F. 

Kemp Opp.  324 

12(5.  View  of  Nai)ias  Creek,  below  California  Bar,  after  a  freShet. 

Photographe<i  by  J.  F.  Kemp Opp.  334 

127.  Sections  to  illustrate  typical  gold   veins  in  tbe  Boise  granite 

region,  Idaho.     After  W.  Lindgren 326 

128.  Geological  cro.ss  section  at  Mercur.  Utah.     After  J.  E.  Spurr. . . .  330 

129.  Diagram  showing  relations  of  ore  to  fault  in  Tunnel  No.  3,  3Iar- 

ion  mine,  Mercur,  Utah.     After  J.  E.  Spurr 331 

130.  Section  along  the  Gey.ser  mine  tunnel,  Mercur,  Utah.     After  J. 

E.  Spurr. 331 

131.  View  of  open  cut,  showing  pay  streak  at  Mercur,  Utah.     From  a 

photograph  by  P.  K.  Hudson Opp.  332 

132.  The  Golden  Gate  cyanide  mill,  Mercur,  Utah.     From  a  photo- 

graph by  L.  E.  Riter.  Jr Ojip.  332 

133.  Two  sections  of  the  argentiferous  sandstone  of  Silver  Reef,  Utah. 

After  C.  M.  Rolker. 333 

134.  Section  of  the  Comstock  Lode  on  the  line  of  Sutro  tunnel.    After 

G.  F.  Becker 341 

135.  Geological  section  of  the  Calico  district,  California.     After  W. 

Lindgren 351 

136.  View  of  the  Handsburg,  California,  looking  southeast.     Schists 

underlie  the  town,  but  the  hills  are  eruptive.     From  a  photo- 
graph by  H.  A .  Titconib Opp.   350 

137.  View  of  the  Stevens  hydraulic   placer  mine,  Auro  City,  Colo. 

From  a  photograph Opp-  350 

138.  View  in  the  Malakolf  hydraulic  placer  mine,  North  Bloomfield, 

Calif.     From  a  photograph Cpp.  351 

139.  View  of  the  Malakolf  hydraulic  placer  mine.  North  Bloomfield, 

Calif.     From  a  i)liotograph OpP-  351 


■■4 

PAon 

'.4 

)er  con- 

•'f 

?..Opp.  312 

i 

,  Black 

'i.r 

,  ..Opp.  312 

)rpliyry 

J 

313 

'^■i 

irbonif- 

■•^ 

loliu  D. 

,i; 

...Opp.  31!! 

■i 

Plioto- 

'i 

...0pp.  3l;i 

1 

;  above 

►'..Opp.  31,s 

d  by  J. 

.< 

...Opp.  318 

L^ 

fter  W. 

'■> 

818 

Illus- 

'-?i 

y  J.  F. 

)\ 

. .  Opp.  324 

1^ 

freSliet. 

...Opp.  334 

'^ 

granite 

\ 

320 

. 

urr 380 

;j,  Mar- 

331 

-; 

^fter  J. 

■:4 

331 

'1 

From  a 

■i 

..Opp.  332 

i 

plioto- 

■:4 

...0pp.  3:!2 

'.  Utali. 

'M 

333 

M 

After 

■'1 

341 

M 

'ter  W. 

'=■? 

351 

::i 

Schists 

4 

photo- 

t 

.  .Opp.   35(1 

^ 

y,  Colo. 

. .  .Opp.  3r)(i 

■■;: 

)miield, 

$ 

...Opp.  3.V. 

"^ 

niifield, 

..* 

...Opp.  351 

LIST  OF  UJA'STRATIONS.  xxi 

KIO.  ""■ 

140.  Generalized  .section  of  a  deep  gravel  bed,  with  technical  terms. 

After  H.  K.  Krowtie 355 

141.  Section  of  Forest  Hill  Divide,  Placer  Co.,  CaUf.,  to  iUastrate  the 

relations  of  old  and  modern  lines  of  drainage.     After  R.  E. 
Browne 350 

142.  North  Star  vein,  Orass  Valley,   Calif.,   showing  quartz  vein  in 

brecciated  and  altered  diabase.     After  W.  Lindgren Opp.  3()3 

143  and  144.  Ore  slioots  of  Nevada  City  and  Grass  Valley  mines,  Calif. 

After  W.  Lindgren 304 

145.  Section  of  the  Pittsburg  vein,  ninth  level,  Nevada  City  district, 

Calif.     From  U.  S.  Geological  Survey 365 

14().  Geological  section  at  Merrifield  vein.  Providence  claim,  Nevada 

City  district,  Calif.     After  W.  Lindgren 366 

147.  Cross-section  of  vein  in  St.  Jolm  mine,  fifth  level,  Nevada  City 

district.  Calif.     After  W.  Lindgren 366 

148.  Cross-section  of  the  Maryland  vein,  in  slope  above  1500-foot  level, 

(hass  Valley  district,  Calif.    After  W.  Lindgren 367 

14!t.  Cross-section  of  the  Bnniswick  vein,  on  the  TOO-foot  level,  Grass 

Valley  district,  Calif.     After  W.  Lindgren 308 

150.  Western  half  of  Geological  map  of  the  Yukon  Gold  Belt,  and  ad- 

jacent regions.     (See  Fig.  151 ) 386 

151.  Eastern  half  of  (Geological  map  of  the  Yukon  Gold  Belt,  and  ad- 

jacent regions.     After  J.  E.  Spurr 387 

152.  Map  of  the  Juneau  mining  district.  Southeast  Alaska.     After  G. 

F.  Becker 392 

153.  Sketch  map  of  Nova  Scotia  Gold  Fields.     After  E.  Gilpin 398 

154.  Cross-section  of  a  Bauxite  deposit  in  Georgia.     After  C.  Willard 

Hayes 405 

155.  Sections  of  the  Crimora  manganese  mine,  Virginia.     After  C.  E. 

Hall 418 

156.  Geological  sections  illustrating  the  formation  oi  manganese  ores 

in  Arkansas.     After  R.  A.  F.  Penrose 419 

157.  The  Turner  mine,   Batesville  region,  Arkansas.     After  R.  A.  F. 

Penrose , , .  420 

158.  Section    of   tlie  Great  Western    cinnabar  mine.     After  G.   F. 

Becker 426 

159.  Map  and  section  of  Gap  Nickel  mine,   Lancaster  Co.,  Penn. 

After  J.  F.  Kemp 433 

100.  Geological  section-map  of  the  Sudbury  district,  Ontario.     After 

by  T.  L.  Walker 435 

101  and  162.  View  of  Copper  Cliff  mine,  Sudbury,  Ontario.    Photo- 
graphs by  T.  G.  Wliite Opp.  436 

1G3.  Horizontal  section  of  the  Etta  granite  knob.  Black  Hills,  S.  D. 

After  W.  P.  Blake 442 


Aim 

Amt 
xiini 


A  nn 

Bot>i 
Bull 
Bull 

B.    1 

Neiu 

Oest 

Phil 
Brui 

Pro( 

Proc 

Prot 

Hay, 

] 
Tmi 

] 
Tnih 


ABBREVIATIONS. 


If 

I 

f 


Amcr,  Assoc.  Adv.  Sci.,  or  A.  A.  A.  S. — Proceedings  of  the  American  As- 
sociation for  the  Advancement  of  Science. 
Amer.  Oeol. — American  Geologist.     Minneapolis,  Minn. 
Awer.  Jour.  Sci. — American  Joiinud  of  Science,  also  k.iown  as  Silliinaii'.H 

Jonrnal.     Fifty  half- yearly  volumes  make  a  stries.     The  t/o»/v/a/ is 

now  (1898)  in  the  third  series.     In  the  references  the  series  is  given 

first,  then  the  volume,  then  the  pige. 
Ann.  lies  Mines — Annules  des  Mines.     Paris,  France. 
Bost.  Soc.  Nnt.  Hint. — See  Proceedings  of  s<'ime. 

liidl.  Geol.  Soc.  Anier. — Bulletin  of  the  (ieological  So(nety  of  America. 
Bull.  3I11S.  Coinp.  Zoill. — bulletin  of  the  Museum  of  Comparative  Zoology, 

Harvard  University.     Camhridge,  Jhiss. 
B.   nnd  H.    ZeihiiKj. — lier(/-  nnd  Huettenmiinnische  Zeitnng.     Leipzig, 

(jiermany. 
Nencs  Jidirh. — Neues  Jahrhuch  fiir  Mineralogie,  Geologie  und  Pala'on- 

tologie,  often  called  Leouhard's  Jahrhuch.     Stuttgart,  (Germany. 
Ocuf.  Zeif. /.  Berg.  n.  IlHett.—Oesterreichische  Zeitschrift  fi'ir  Berg- und 

Hiictd'inre.'^en.     Vienna.  Austria. 
Fhilos.  Mug. — Pliilosopliicul  Magazine.       Edinburgh,  Scotland. 
Vrue.  Amer.  ^l(V>(/.— Proceedings  of  the  American  Academy  of  Arts  and 

Sciences.     Boston,  JIass. 
Proc.  and  Trans.  N.  S.  Inst.  Nat.  .Sc/.— Proceedings  and  Transjictions  of 

the  Nova  Scotia  Institute  of  Natural  Science.     Halifax.  Nova  Scotia. 
I'roc.  Host.  Soc.  iXat.  ///.sY. —Proceedings  of  the  Bcston  Society  of  Natural 

History.     Boston,  Mass. 
Pruc.   Colo.  Sci.  -Soc— Proceedings  of  the   Colorado  Scientific  Society. 

Denver,  Colo. 
h'dHmoud's  A'(7;o//,s-.— Mineral  Resources  West  of  the  Rocky  Mountains, 

Washington,  1867-1876.     The  tivst  two  volumes  were  edited  by  J.  Ross 

Browne,  the  others  by  R.  W.  Raymond. 
Trans.  Amer.  Inst.  Min.  £;ij/.— Transactions  of  the  American  Institute  of 

Mining  Engineers. 
Trans.  Min.  A.%soc.  and  LlhI.,  Corjwra?/.— Transactions  of  the  Mining  As- 
sociation and  Institute  of  Cornwall.     Tuckingmill,  Camborn,  England. 


XXIV 


AJiBliKVlATIONS. 


TrniiH.  N.  Y.  Anid.  of  Sd. — Tniiisiu'tu»tis  of  tlio  New  York  At'ivdemy  of 

ScietKres,  fornicily  the  Lyceum  itl'  Niitiinil  Hi.storj'. 
Xcit.  <l.  tl.  (J.   QvH. — ZcitHchrift  dvr  (IciilHcfwn  gcoloym'Iien  (tvscllHchaft. 

Hcilin,  (ieriimiiy. 
Zeilscli.  f.  Ji.,  11.  itnil  S.  ini.  P.  St. — XeitsvliriJ't  Jin-  liciy-,  Jltuttiii-,  und 

SalincriU'CHcn  iin  I'vcHHHixehcn  Stoat.     Berlin,  (jernmny. 
Zcitsclir.  f.  A';7/,s. — X<'it.scliriJ't  fiir  Kri/sfdllixjiutpliic.     IMiinicli,  (Jerinany. 
ZcitHchf.prald.  (icol. — Zeitsehrift  ITir  ])riiklis('lie  tieologie.     Berlin,  (Jer- 

niuny. 

The  remaining  abbreviations  are  deemed  Helf-explanatory.  The  num- 
bering of  the  |)iuagra[)lis  is  on  tiio  following  jirinciple:  The  first  digit 
refers  invariably  to  the  part  of  the  book,  the  second  digits  to  the  chapter, 
and  the  laat  two  to  the  paragraph  of  the  chapter. 


cudemy  of 

I'sclhchaft. 

at  ten-,  und 

(rorinany. 
Jerlin,  (Jer- 

The  num- 

first  (liK'l 

lie  chapter. 


PART  I. 


INTRODUCTORY. 


4 


CHAPTER  I. 


GENERAL  GEOLOGICAL   FAtTS   AND    PRINCIPLES. 

1.01.01.^  In  the  advance  of  geological  science  the  stand- 
])oiuls  from  wbich  the  strata  forming  the  earth's  crust  are  re- 
garded necessarily  change,  and  new  points  of  view  are  estab- 
lislied.  In  the  last  few  years  two  have  become  especially 
prominent,  and  there  are  now  two  sharply  contrasted  positions 
from  which  to  obtain  a  conception  of  the  structure  and  develop- 
ment of  the  globe.  The  first  is  the  physical,  the  second  the 
biological.  For  example,  we  consider  the  surface  of  the  earth 
as  formed  by  rocks,  differing  in  one  i)art  and  another,  and 
those  different  rocks  or  groups  of  rocks  are  known  by  different 
names.  The  names  have  no  special  reference  to  the  animal 
remains  found  in  them,  but  merely  indicate  that  series  of  re- 
lated strata  form  the  surface  in  particular  regions.  ( )n  the 
other  hand,  the  rocks  are  also  regarded  as  having  been  formed 
in  historical  sequence,  and  as  containing  the  remains  of  organ- 
isms characteristic  of  the  period  of  their  formation.  They  illus- 
trate the  development  of  animal  and  vegetable  life,  and  in  this 
way  afford  materials  for  historical-biological  study.  In  the 
original  classification,  the  biological  and  historical  considera- 
tions cire  all-important.  But  when  once  the  rocks  are  placed  in 
their  true  position  in  the  scale,  and  are  named,  these  considera- 
tions, for  many  purposes,  no  longer  concern  us.  The  forma- 
tions are  regarded  simply  as  members  in  the  physical  constitu- 
tion of  the  outer  crust.  The  International  Geological  Congress 
held  in  Berlin  in  ISSo  expressed  these  different  points  of  view 
hi  two  parallel  and  e(}uivalent  series  of  geological  terms,  which 


'  Tlie  mxmbers  at  the  begiuiiiiifj;  of  tlie  iKiragriii)hs  are  s  arranged  tliat 
llii'  lirst  ligure  denotes  tlie  i)art  oftlie  })ook,  tiie  nt.'xt  two  ligiires  tlie  cliap- 
tL'i-,  and  the  last  two  tlie  paragrajjli.  Thus  L0G.:;2i  means  I'art  I.,  Chairter 
VI.,  Paragraph  21  under  Chapter  VI. 


I:V 


KEMP'S  ORE  DEPOSITS. 


are  tabulated  on  p.  4.  They  are  now  very  generally  adopted. 
For  clearness  in  illustration,  the  equivalent  terms  employed  by 
Dana  are  appended. 


Biological  Terms. 

Physical  Terms. 

iJajia's  Terms. 

Hlvstrations 

Era. 

Group. 

Time. 

Paleozoic. 

Period. 

System. 

Age. 

Devonian 

Epoch. 

Series. 

Period. 

Hamilton. 

Age. 

Stage. 

Epoch. 

Marcellus. 

The  United  States  Geological  Survey  divides  as  follows:  Era 
and  System,  Period  and  Group,  Epoch  and  Formation.  In 
considering  the  ore  deposits  of  the  country,  we  employ  only  the 
physical  terms.  We  understand,  of  course,  the  chronological 
position  of  the  systems  in  historical  sequence,  hut  it  is  of  small 
moment  in  this  connection  what  may  be  the  forms  of  life  in- 
closed in  them.  The  purely  physical  character  of  the  rocks — 
whether  crystalline  or  fragmental;  whether  limestone,  sand- 
stone, granite  or  schists;  whether  folded,  faulted,  or  undis- 
turbed— are  the  features  on  which  we  lay  especial  stress.  In 
all  the  periods  the  same  sedimentary  rocks  are  repeated,  and 
in  the  hand  specimen  it  is  almost  always  impossible  to  distin- 
guish those  of  different  ages  from  one  another.  The  classifi- 
cation, briefly  summarized,  is  as  follows: 

1.01.0'^.  Archean  Group. — I.  Laurentian  System.  II. 
Huronian  System,  Additional  subdivisions  have  been  intro- 
duced by  Canadian  and  Minnesota  geologists  (Animikie,  Mont- 
albau,  etc.),  and  it  is  a  growing  custom  to  call  all  those  which 
are  sediments  or  later  than  sediments,  especially  in  the  region 
of  the  Great  Lakes,  by  the  name  of  Algonkian.  (See  discus- 
sion under  Example  D.) 

Paleozoic  Group.— III.  Keweenawan  System.  (This 
may  belong  with  the  Archean.)  IV.  Cambrian  System:  (a) 
Georgian  Stage;  {!))  Acadian  Stage;  (c)  Potsdam  Stage.  V. 
Lower  Silurian  System.  (^4)  Canadian  Series:  {a)  Calcifer- 
ous  Stage;  (6)  Cliazy  Stage.  (This  will  probably  experience 
revision.)  (/?)  Trenton  Series:  (a)  Trenton  Stage;  (/>)  Utica 
Stage;  (c)  Cincinnati  or  Hudson  River  Stage.  VI.  Upper 
Silurian  System.  (^)  Niagara  Series:  (a)  Medina  Stage;  {h) 
Clinton  Stage;  (c)  Niagara  Stage.  (/>)  Salina  Series.  (C) 
Lower  Helderberg  Series.  VII.  Devonian  System.  (^1)  Oris- 
kany  Series,     (i^j  Corniferous  Series;    (a)  Cauda-Galli  Stage; 


UKyKHAL   Ul-:OLOaiCAL  FACTS  AXJJ  ritlNCIPLES. 


■  adopted, 
ployed  by 

\rations. 
eozoic. 
^'onian. 
iiiilton. 
•cellus. 

lows:  Era 
ition.  Ill 
y  only  the 
anological 
s  of  small 
of  life  iu- 
le  rocks — 
one,  sand- 
or  iindis- 
itress.  In 
sated,  and 
!  to  distin- 
le  classifi- 

tem.  II. 
een  intro- 
iie,  Mont- 
)se   which 

he  region 
ee  discus- 

(This 

stem:  (a) 

tage.     V. 

Calcifer- 

x])erience 

{h)  UticH 

^I.  Upper 

>tage;  {b) 

i-ies.     (C) 

{A)  Ov\^- 

illi  Stage: 


(/>)  Schoharie  Stage;  (c)  Corniferous  Stage.  (C)  Hamilton 
Series:  («)  Marcellus  Stage;  {b)  Hamilton  Stage;  (c)  Genesee 
Stage.  (Z>)  Chemung  Series:  («)  Portage  Stage;  (/>)  Chemung 
Stage.  VIII.  Carboniferous  System,  (.1)  Sub-carboniferous 
or  Mississippian  Series.  {B)  Carboniferous  Series.  (C) 
Permian  L'eries. 

Mesozoic  Group. — IX.  Triassic  System.  X.  Jurassic  Sys- 
tem. IX.  and  X.  are  not  sharply  divided  in  the  United  States, 
and  we  often  speak  of  Jura-Trias.  A  stratum  of  gravel  and 
sand,  along  the  Atlantic  coast,  that  contains  Jurassic  fossils 
Ills  been  called  the  Potomac  formation  by  McGee.  XL  Cre- 
taceous System.  Subdivisions  differ  in  different  parts  of  the 
country.  Atlantic  Border:  (a)  Raritan  Stage;  {b)  New  Jer- 
sey Greensand  Stage.  Gulf  States:  {<()  Tuscaloosa  Stage;  {b) 
Kutaw  Stage;  (c)  Rotten  Limestone  Stage;  {d)  Ripley  Stage. 
Rocky  Mountains:  {a)  Comanche  Stage;  (6)  Dakota  Stage:  (c) 
Ik'uton  Stage;  {(I)  Niobrara  Stage;  (e)  Pierre  Stage;  (/)  Fox 
Hills  Stage;  {g)  Laramie  Stage.  Stages  (c)  and  {d)  are 
sometimes  collectively  called  the  Colorado  Stage;  while  (e) 
and  (/)  are  grouped  as  the  Montana  Stage.  Pacific  Coast:  (a) 
Shasta  Stage;  {b)  Chico  Stage. 

Cexozoic  Group. — XII.  Tertiary  System.  Gulf  States. 
(.1)  Eocene  Series:  Midway,  Lignitic,  Lower  Claiborne,  Clai- 
borne. Jackson  and  Vicksburg  Stages.  {B)  Oligocene,  want- 
ing. (C)  Miocene  Series,  Chattahoochee,  Chipola  and  Chesa- 
peake Stages.  {!))  Pliocene  Series:  Floridian  Stage.  Interior 
llegion.  (^1)  Eocene  Series :  Puerco,  Torrejon,  Wasatch,  Wind 
liiver,  Bridger  and  Uinta  Stages.  {B)  Oligocene  Series:  White 
Itiver  Stage.  (C)  Miocene  Series:  John  Day,  Deep  River, 
.111(1  Loup  Fork  Stages.  {D)  Pliocene  Series:  Good-night 
(Palo  Duro)  and  Blanco  Stages.  Pacific  Coast.  The  Eocene 
is  called  the  Tejon.  Miocene  and  Pliocene  are  used  for  the 
others. 

XIII.  Quaternary  System.  {A)  Glacial  Series.  (Z?) 
Chainplam  Series,  (C)  Terrace  Series.  (Z))  Recent  Series. 
Pleistocene  is  sometimes  employed  as  a  name  for  the  early 
Quaternary,  especially  south  of  the  Glacial  Drift.  In  accord 
with  the  practice  of  the  U.  S.  Geological  Survey,  the  Tertiary 
is  now  generally  divided  into  the  Eocene  and  the  Neocene  (in- 
f hiding  Oligocene,  Miocene  and  Pliocene)  series. 


iS^ 


I  i 


6 


KI'JMP'S  out!  UEPOSITS. 


Other  terms  aro  also  often  used,  especially  when  we  do  not 
wish  to  speak  too  detinitely.  "Formation"  is  a  word  loosely 
employed  for  any  of  the  above  divisions.  "Terrane"  is  used 
much  in  the  same  way,  but  is  rather  more  restricted  to  the 
lesser  divisions.  A  stratum  is  one  of  the  larger  sheet-like 
masses  of  sedimentary  rock  of  the  same  kind;  a  bed  is  a 
thinner  subdivision  of  a  stratum.  "Horizon"  serves  to  indi- 
cate a  particular  position  in  the  geological  column;  thus, 
speakiug  of  the  Marcellus  Stage,  we  say  that  shales  of  this 
horizon  occur  in  central  New  York. 

1.01.03.  The  rock  species  themselves  are  classified  into 
three  great  groups — the  Igneous,  the  Sedimentary,  and  the 
Metamorphic. 

The  Igneous  (synonymous  terms,  in  whole  or  in  part :  massive, 
eruptive,  volcanic,  plutonic)  include  all  those  which  have 
solidified  from  a  state  of  fusion.  Thej^  are  marked  by  three 
types  of  structure — the  granitoid,  the  porphyritic,  and  the 
glassy,  depending  on  the  circumstances  under  which  they 
have  cooled.  Under  the  first  type  of  structure  come  the 
granites,  syenites,  diorites,  gabbros,  diabases,  and  peri- 
dotites;  under  the  second,  quartz-porphyries,  rhyolites,  por- 
phyries, trachytes,  porphyrites,  andesites,  and  basalt;  under 
the  third,  pitchstone,  obsidian,  and  other  glasses. 

The  Sedimentary  rocks  are  those  which  have  been  deposited 
in  water.  They  consist  chiefly  of  the  fragments  of  pre-existing 
rocks  and  the  remains  of  organisms.  They  include  gravel, 
conglomerate,  breccia,  sandstone — both  argillaceous  and  cal- 
careous—shales, clay,  limestone,  and  coal.  In  volcanic  dis- 
tricts, and  especially  where  the  eruptions  have  been  subma- 
rine, extensive  deposits  of  volcanic  lapilli  and  fine  ejectments 
have  been  formed,  called  tuffs.  With  the  sedimentary  rocks  we 
place  a  few  that  have  originated  by  the  evaporation  of  solu- 
tions, such  as  rock  salt,  gypsum,  etc. 

The  Metamorphic  rocks  are  usually  altered  and  crystallized 
members  of  the  sedimentary  series,  but  igneous  rocks  arc 
known  to  be  subject  to  like  change,  especially  whan  in  the 
form  of  tuffs.  They  are  all  more  or  less  crystalline,  more  or 
less  distinctly  bedded  or  laminated,  of  ancient  geological  age 
or  in  disturbed  districts.  They  include  gneiss,  crystalline 
schists,  (]uartzite,  slate,  marble,  and  serpentine. 


OENERAL  (JEOLOGICAL  FACTS  AND  PRINCIPLES. 


t 


After  a  brief  toj)ograpliical  survej-.  we  shall  employ  the 
above  terms  to  summarize  the  get)k)gical  structure  of  the 
United  States.  The  several  purely  artificial  territorial  divi- 
sions are  made  simply  for  convenience.  Nothing  but  intelli- 
gent travel  will  perfectly  acquaint  one  with  the  topographical 
and  geological  structure  of  the  country,  and  in  this  connection 
Macfarlane's  "Geological  Railway  Guide"  and  a  geological 
map  are  indispensable. 

1.01.04.  On  the  east  we  note  the  great  chain  of  the  Appa- 
lachians, with  a  more  or  less  strongly  marked  j)laiu  between  it 
and  the  sea.  This  is  especially  developed  in  the  south,  and  is 
now  generally  called  the  Coastal  Plain.  It  is  of  late  geologi- 
cal age,  and  contains  the  pine  barrens  and  seacotist  swamps. 
The  Appalachians  themselves  consist  of  many  ridges,  running 
on  the  north  into  the  White  Mountains,  the  Green  Mountains, 
and  the  Adirondacks.  Farther  south  the  Highlands  of  Now 
York  and  New  Jersey,  the  South  Mountain  of  Pennsylvania, 
the  Alleghenios,the  Blue  Ridge,  and  the  other  southern  ranges 
make  up  the  great  eastern  continental  mountain  system.  In 
western  New  York  and  Ohio  we  find  a  rolling,  hilly  country; 
in  Kentucky  and  Tennessee,  elevated  tableland,  with  deeply 
worn  river  valleys.  Indiana,  Illinois,  Iowa,  and  Missouri  con- 
tain prairie  and  rolling  country,  more  broken  in  southern  Mis- 
souri b}^  the  Ozark  uplift.  In  Michigan,  Wisconsin,  and  Minne- 
sota, the  surface  is  rolling  and  hilly  with  niimerous  lakes.  In 
Arkansas,  Louisiana,  and  Mississippi  there  are  bottom  lands 
along  the  Mississippi  and  Gulf  with  low  hills  back  in  the  interior. 
Across  Arkansas  and  Indian  Territory  runs  the  east  and  west 
Ouachita  u])lift.  West  of  ihese  States  comes  the  region  of 
the  great  jilains,  and  then  the  chain  of  the  Rocky  Mountains, 
consisting  of  high,  dome-shaped  peaks  and  ridges,  with  ex- 
tended elevated  vallej's  (the  parks)  between  the  ranges.  Some 
distance  east  of  the  main  chain  are  the  Black  Hills,  made  up 
of  later  concentric  formations  around  a  central,  older  micleus. 
To  the  east  lies  also  the  extinct  volcanic  district  of  the 
Yellowstone  National  Park,  In  western  Colorado,  Utah, 
and  New  Mexico,  between  the  Rocky  Mountains  and  the 
Wasatch,  is  the  Colorado  plateau,  an  elevated  tableland. 
This  is  terminated  by  the  north  and  south  Wasatch  range, 
and  is  traversed  east  and  west  by  the  Uintah  range.     To  the 


8 


KEMP'S  ORE  DEPOSITS. 


west  lies  the  region  called  the  Great  Basin,  characterized  by- 
alkaline  deserts,  and  subordinate  north  and  south  ranges  of 
mountains.  Next  conies  the  chain  of  the  Sierra  Nevada,  and 
lying  between  it  and  the  Coast  range  is  the  great  north  and 
south  valley  of  California.  This  rises  in  the  comparatively 
low  Coast  range,  which  slopes  down  to  the  Paciiic  Ocean. 
To  the  north,  these  mountains  extend  into  eastern  Oregon 
and  Washington,  with  forests  and  fertile  river  valleys. 
These  topographical  features  are  important  in  connection 
with  wliat  follows,  for  the  reason  that  the  ore  dej)osits 
especially  favor  moimtainous  regions.  Mountains  them- 
selves are  due  to  geological  disturbances — upheaval,  folding, 
faulting,  etc. — and  are  often  accompanied  by  great  igneous 
outbreaks.  They  therefore  form  the  topographical  surround- 
ings most  favorable  to  the  development  of  cavities,  waterways, 
and  those  subterranean,  mineral-l)earing  circulations  which 
would  fill  the  cavities  or  replace  the  rock  with  useful  min- 
erals. 

1.01.05.  Geoloijical  Outline.  I.  Neiv  England,  New  York, 
New  Jersey,  and  Eastern  Pennsylvania  District. — In 
New  England  and  northern  New  York  the  Archean  is  espe- 
cially developed,  forming  the  White  Mountains,  the  Adiron- 
dacks,  and  the  Highlands  of  New  York  and  New  Jersey. 
These  all  consist  oi  granite  and  other  igneous  rock,  of  gneiss, 
and  of  crj'stalline  schists.  There  are  also  great  areas  of  meta- 
morphic  rocks  whose  true  age  may  be  later.  The  Green  Moun- 
tains are  formed  of  such,  and  were  elevated  at  the  close  of  the 
Lower  Silurian.  In  New  England  there  are  small,  scattered 
exposures  of  the  undoubted  Paleozoic  (Devoniarn,  Carbonif- 
erous). In  eastern  Ne\v  York,  and  to  some  extent  in  New  Jer- 
sey and  eastern  Pennsylvania,  the  entire  Paleozoic,  except  the 
Carboniferous,  is  strongly  developed.  Up  and  down  the  coast 
there  are  narrow  north  and  south  estuary  deposits  of  red  Jura- 
Trias  sandstone,  which  are  pierced  by  diabase  eruptions.  The 
Cretaceous  clays  are  strong,  and  the  Tertiarj-  strata  occur  at 
Martha's  Vineyard,  in  Massachusetts,  while  over  all,  as  far 
south  as  Trenton,  is  found  the  glacial  drift.  Between  the 
Archean  ridges  of  the  Highlands,  and  the  first  foldings  of  the 
Paleozoic  on  the  west  is  found  the  so-called  Great  Valley, 
which  also  runs  to  the  south  and  is  a  very  important  topo- 


GENERAL  dKOLOGICAL   FACTS  AND  PRTNCTPLES. 


r 


graphic  and  geologic  foatiire.     It  follows  the  outcrop  of  the 
Siluro-Canihriau  limestones,  to  whose  erosion  it  is  due. 

II.  Eastern-Middle  and  Soiifheasfern  Coast  District. — 
The  low  plains  of  the  coast  are  formed  by  Quaternary,  Terti- 
ary, and  Cretaceous,  consisting  of  gravel,  sand,  shell  beds,  and 
cla}'.  Inland  there  are  ex])osures  of  J'lra-Trias,  as  in  the 
north.  The  Archean  crystalline  rocks  are  also  seen  at  numer- 
ous jioints  not  far  from  the  ocean.  Florida  is  largely  made 
up  of  limestones,  with  a  mantle  of  calcareous  sand. 

III.  Allegheni/  Jiegioii,  and  tJie  Central  Phdeaii. — The 
Api)alachian  mountain  system,  from  New  York  to  Alabama, 
cousists  principallj'of  folded  Paleozoic  (largel 3'  Carboniferous), 
witii  Archean  ridges  on  its  eastern  flank.  There  is  an  enor- 
mous development  of  folds,  with  northeast  and  southwest  axes. 
On  the  west  they  are  succeeded  by  tlie  ])lateau  region  of  Ken- 
tucky and  Tennessee,  ohiell}'  Paleozoic.  Along  central  latitudes 
the  Archean  does  not  appear  again  east  of  the  ACississippi. 

IV.  Region  of  the  (ireat  Lakes. — In  j\lichigan,  Wiscon- 
sin, and  Minnesota  the  Archean  rocks  are  extensively  devel- 
oped, both  Laurentian  and  Huronian.  Around  Lake  Superior 
are  found  the  igneous  and  sedimentary  rcjcks  of  the  Keweena- 
wan,  followed  by  the  lower  Paleozoic.  Lake  Michigan  and 
Lake  Huron  are  surrounded  by  Silurian,  Devonian,  and  Car- 
boniferous; Lake  Erie  by  Devonian;  Lake  Ontario,  by  Silu- 
rian. Kunuing  south  through  Ohio,  we  find  an  important  fold 
known  as  the  Cincinnati  uplift,  with  a  north  and  south  axis. 
It  was  elevated  at  the  close  of  the  Lower  Silurian.  In  the 
lower  peninsula  of  Michigan  and  in  eastern  Ohio  and  western 
Pennsylvania  the  Carboniferous  is  extensively  developed. 

Y.  Mississippi  Vallet/. — The  headwaters  of  the  Mississippi 
are  in  the  Archean.  It  then  pass(>s  over  Cambiian  and  Silu- 
rian strata  in  Minnesota.  Wisconsin,  northern  Iowa,  and  Illi- 
nois, wliich  in  these  States  lie  on  the  Hanks  of  the  Archean 
"Wisconsin  Island"  of  central  Wisconsin.  These  are  suc- 
ceeded by  subordinate  Devonian,  and  in  Southern  Iowa.  Illi- 
nois, and  Missouri  by  Carboniferous.  In  southern  Missouri 
the  Lower  Silurian  forms  the  west  bank.  Thence  to  the  ( lulf 
tlie  river  tlows  on  estuary  deposits  of  Quaternary  age,  with 
Tertiary  and  Cretaceous  farther  inland. 

YI.  The  Gulf  Region. — The   Gulf  States  along  the  water 


[0 


K/'JM/'S  ORK  JJEPOSITS. 


front  aro  formed  by  the  Qufitoniary.  TIiih  in  soon  succeeded 
inland  by  very  extensive  Tertiary  beds,  which  aro  the  })rinci- 
\M\\  formation  represented. 

VII.  Tin'  (t'rctif  P/<iiiis. — West  of  the  Paleozoic;  rocks  of 
the  States  bordering  on  the  Mississippi  is  found  a  hroad  strip 
of  Cretaceous  running  from  the  Gulf  of  Mexico  to  and  across 
British  America,  and  bounded  on  the  west  by  the  foothills  of 
the  Hocky  Mountains.  A  few  Tertiary  lake  deposits  are  found 
in  it.  Quite  extt^nsivc^  Triassic  rocks  are  devel()])ed  on  the 
south.  The  surface  is  a  gradually  rising  j'lateau  to  the  Rocky 
Mt)untains. 

VIII.  Re<iion  of  ihe  Rocky  Moviitains^  the  ninck  Hills, 
and  the  Yelloivfitoue  National  Park.  The  Rocky  Mountains 
rise  from  the  yuviiries  in  long  north  and  south  ranges,  consist- 
ing of  Archean  or  Algonkian  axes  with  the  Paleozoic  in 
relatively  small  amount  in  Colorado,  hut  i)resent  in  a  large  cross- 
section  in  jMontana.  There  is  abiuulant  Mesozoic  on  the  east 
and  Avest  flanks.  In  the  parks  are  found  lake  deposits  of  Ter- 
tiary age.  There  are  also  great  bodies  of  igneous  rocks,  which 
attended  the  various  upheavals.  The  juMucipal  uplieavals 
began  at  tlie  close  of  the  Cretaceous.  The  outlying  Black 
Hills  consist  of  an  elliptical  Archean  core,  with  concentric 
Paleozoic  and  Mesozoic  strata  laid  up  around  it.  1'he 
National  Park  consists  chiefly  of  igneous  (volcanic)  rocks  in 
enormous  development, 

IX.  Colorado  Plateau. — The  Rocky  Mountains  shade  out 
on  the  Avest  into  a  great  elevated  plateau,  extending  to  central 
Utah,  where  it  is  cut  off  by  the  north  and  south  chain  of  tli(> 
Wasatch.  The  Uintah  Mountains  are  an  east  and  west  chain 
in  its  northern  portion.  The  rocks  on  the  north  are  chief!}"  Terti- 
ary, with  Mesozoic  and  Paleozoic  in  the  mountains.  To  the 
south  are  found  Cretaceous  and  Triassic  strata,  with  igneous 
rocks  of  great  extent.  The  princijial  u])heaval  of  the  Wasatch 
began  at  the  close  of  the  Carboniferous,  and  seems  still  to  be  in 
progress. 

X.  Rerjion  of  the  Great  Basin. — Between  tiie  Wasatch 
and  the  Sierra  Nevada  raiiges  is  found  the  Great  Basin  region, 
once  lake  hottoms.  now  very  largelj^  alkaline  plains  of  Qua- 
ternary age.  The  surface  is  diversified  by  subordinate  north 
and  south  ranges,  formed  by  great  outflows  of  eruptive  rocks, 


OENEltAL  GEOLOGICAL  FACTS  AND  PIUNCIPLE8.        H 


and  by  tiltoJ  Paleozoic.  The  rangos  nreextensivply  bn^kou  mid 
the  Btratilied  rocks  often  lie  in  confused  aud  irregular  poHitions. 
There  is  no  drainage  to  the  ocean. 

XI.  Ecgioii  of  the  Pucijic  Hlope. — The  depression  of  the 
Great  Basin  is  succeeded  by  tlie  heights  of  the  Sierra  Nevada. 
On  the  west  the  Sierras  slope  down  into  the  Central  Valley  of 
California.  The  flanks  are  largely  nujtaniorphosod  Jurassic 
and  Cretaceous  rocks  with  great  develo})nieuts  of  igncona  out- 
llows.  The  surface  rises  again  in  the  Coast  ranges,  which  slope 
away  farther  west  to  the  ocean.  In  addition  to  the  Jurassic 
and  Cretaceous,  the  Tertiary  and  Quaternary  are  also  devel- 
oped, and  in  the  Coast  ranges  are  many  outllows  of  igneous 
rock.  The  princi])al  n])heaval  of  the  Sierra  Nevada  began  ^t 
the  close  of  the  Jurassic,  that  of  the  Coast  range  at  the  close 
of  the  Miocene  Tertiary. 

XII.  Reyion  of  the  NoHJnrest. — Washington  and  Oregon, 
along  the  coast,  are  formed  by  Cretaceous  and  Tertiary  strata 
similar  to  California.  But  inland,  innnense  outpourings  of 
igneous  rocks  co\er  the  greater  portion  of  both  States  and  ex- 
tend into  Idaho.  On  the  ncn-th  the  Carboniferous  is  extensive, 
running  eastward  into  Montana.  Quaternary  and  Tertiary 
lake  deposits  are  also  not  lacking. 

l.Ol.OG.  On  tlie  Forms  Assumed  htj  Rock  Masses. — All 
sedimentary  rocks  have  been  orginally  deposited  in  bods,  ap- 
proximately horizontal.  They  are  not  of  necessity  absolutely 
horizontal,  because  they  may  have  been  formed  on  a  sloping  bot- 
tom, or  in  a  delta,  in  both  of  which  cases  an  apparent  dip  ensues. 
We  find  them  now,  however,  in  almost  all  cases  changed  from 
a  horizontal  position  by  movements  caused  primarily  by  the 
compressive  strain  in  the  earth's  crust.  Beds  thus  assume 
folds  known  as  monoclines,  anticlines,  and  SA'nclines. 

A  monocline  is  a  terrace-like  dropping  of  a  bed  without 
clianging  the  direction  of  the  dip.  There  is  usually  a  zone, 
more  or  less  shattered,  along  the  folded  portion,  and  such  a 
zone  may  become  a  storage  receptacle.  Monoclines  of  a  gentle 
(character  in  Ohio,  which  have  been  detected  by  Ortoa  in  stud- 
ies of  natural  gas,  have  been  called  "arrested  anticlines."  An 
anticline  is  a  convex  fold  with  opjiosing  dips  on  its  sides, 
while  a  syncliue  is  a  concave  fold  with  the  dips  on  its  sides 
coming  together.    We  speak  of  the  axis  of  a  fold,  and  this 


19 


KHMPS  0/i'h'  J>l':iH>81TH. 


marks  the  geuoral  direction  of  the  crest  or  trough.  The  axis 
is  soldom  straight  for  auy  groat  distance.  Fohls  aro  ol'tou 
broken  and  faidted  across  the  strike  of  their  axes,  and  this 
causes  what  is  caHod  a  "pitch"  of  the  axes  and  makes  the 
original  dips  run  diagonally  down  on  the  linal  one.  Folds  are 
the  primary  cause  of  the  phenomena  of  dij)  and  strike.  Hori- 
zontal beds  have  neither.  A  dome-like  elevation  of  the  beds, 
with  dijjs  radiating  in  every  direction  from  its  summit,  is 
called  a  (piaijuaversal,  but  it  is  a  rare  thing.  An  anticline  or 
synclino  with  equal  dijjs  on  opposite  sides  of  its  axis  is  called 
a  normal  fold.  If  the  dip  is  steeper  on  one  side  tiiun  on  the 
otliei",  it  is  an  overthrown  fold ;  if  the  sides  are  crushed  to- 
gether, it  is  a  collapsed,  or  sigmoid  fold. 

Igneous  rocks  are  in  the  form  of  sheets  (the  term  "bed'* 
should  be  restricted  to  sedimentary  rocks),  knobs  or  bosses, 
necks,  laccolites,  and  dikes.  A  slieet  is  the  form  naturally  as- 
sumed by  surface  flows,  and  by  an  igneous  mass  which  has 
been  intruded  between  beds.  It  has  relatively  great  length 
and  breadth  as  compared  with  its  thickness,  and  coincides 
with  its  walls  in  dip  and  strike.  A  knob,  or  boss,  is  an  irregu- 
lar mass,  of  approximately  equal  length  and  breadth,  which 
may  be  related  in  any  \\',\y  to  the  position  of  its  walls.  Such 
masses  are  often  left  projecting  by  erosion.  A  neck  is  the  tilled 
conduit  of  a  volcano,  which  sometimes  remains  after  the  over- 
lying material  has  been  denuded.  A  laccolite  is  a  lenticular 
sheet  which  has  spread  between  beds  laterally  from  its  conduit, 
and  thus  has  never  reached  the  surface,  unless  revealed  by  sub- 
secjuent  erosion.  A  dike  is  a  relativel}'  long  find  narroAv  bod}' 
of  igneous  rock  which  has  been  intruded  in  a  fissure.  It  is 
analogous  to  a  vein,  but  the  term  "vein"  ought  not  to  be  ap- 
plied to  an  undoubtedly  igneous  rock.  Some  granitic  mixtures, 
however,  of  quartz,  feldspar,  and  mica,  leave  us  yet  in  uncer- 
tainty as  to  wliether  they  are  dikes  or  veins.  (See  Exam])le  51.) 
From  the  above  it  will  be  seen  at  once  that  bosses,  knobs,  and 
necks  may  be  practically  indistinguishable. 


CHAPTER  II 

THE  FORMATION  OF  CAVITIES  IN   ROCKS   AND   THEIR  SECOND- 
ARY  MODIFICATION — SUBTERRANEAN  WATERS. 

1.02.01.  Tension  Joints. — In  the  contrnction  caused  by  cool- 
ing, drying,  or  hardening,  both  igneous  and  sedimentary  rocks 
break  into  more  or  less  regular  masses  along  division  planes, 
called  joints,  or  diaclases.  Numerous  cracks  and  small  cavities 
icsult.  Basaltic  cohunns,  or  the  jn-isniatic  masses,  formed  by 
the  separation,  in  cooling  and  cons(jlidating,  of  the  heavier 
l)asic  rocks,  along  planes  normal  to  the  cooling  surface,  are 
good  illustrations  of  the  first.  Larger  manifestations  of  them 
often  become  filled  with  zeolites,  calcite,  and  other  secondary 


Fia.  1. — Illustration  of  riftimj  in  granite  at  Cape  Ann,  Mass. 
After  R.  S.  Tarr.     Amer.  Jour.  ofSci.,  April,  1S!U. 

minerals.  Granitic  rocks  and  porphyries  break  up  less  regu- 
larly from  the  same  cause,  but  still  exhibit  prismoids  and 
polygonal  blocks  and  benches.*  Large  cracks  have  been  re- 
ferred to  this  cause,  which  have  afterward  formed  important 
roceptacles  for  ores.  (See  Example  llr/.) 
The  nature  of  the  strain  which  produces  the  Assuring  makes 


'  J.  P.  Iddings'  papier  on  "Tlie  Columnar  Structure  in  the  Igneous  Rocks 
ouOrangf  Mountain,  N.  J.,"  Amer.  Jour.  Sci.,  III.,  xxxi.  ;W0,  is  an  oxcel- 
ient  discussion. 


I 


u 


hh'Mi's  OJU'J  Dh'Posrrs. 


\  f 


th(<  t«M'm ''tonsion  joint"  an  oxciOlcnt  nunio  for  tlicm.'  Tln'ro 
aro,  liovvevtT,  otiior  varieticH  of  tension  jointH.  Sedimentary 
rockH,  tliat  contain  a  large  (jnantityof  wator  wlion  lirst  formed, 
may  lose  it  in  whole  or  in  part,  and  may  ulirink  and  crack  for 
thin  reason,  i)rccisely  as  does  the  nnid  on  tlic^  liottoni  of  a  dried 
puddle.  Ledj^oH  in  many  j)artH  of  the  woild  are  exposed  during 
the  day  to  a.  hot  sun,  and  during  the  nigiit  cool  down  to  a  com- 
l)arativ(>ly  lew  teniperatiu'e,  The  alternate  expansion  and  con- 
traction may  produce  tensional  stresses  leading  to  the  produc- 
tion of  joints.  The  concentric  surfaces  of  parting  which  are 
HO  often  thsplayed  in  granite  <iuarrie8,  and  which  resend)le  the 
coats  of  an  onion,  have  heen  referred  to  tins  cause.  When 
stratitii'd  rocks  liecome  folded  into  anticlines  and  synclines, 
tensional  strains  are  developed  in  the  upjier  laj'ers  of  the  anti- 
cline, and  the  lower  layers  of  the  syiicline,  rt>spectively  above 
and  helow  the  surface  of  no  strniu,  Kupture  almost  always 
results,  and  cracks  or  joints  are  produced,  wliieh  run  pjirallel 
with  tiio  ax'H  of  the  fold.  Cross-folding  may  then  develop  au- 
otlier  Heries  at  an  angle  with  the  iirst. 

l.O'l.O'l.  C'lcdt  (!(/(',  Fissililji  (iinl  ('(>mi)re.sm\)ii  Joints.  —  In 
speaking  of  the  etfects  of  i)re8sure  ujxrn  rocks,  it  is  in  many 
respects  convenient  to  follow  again  the  nomenclature  of  Van 
Hise,  as  established  in  the  paper  last  cited,"''  and  to  distinguish 
at  the  outset  between  cleavage  and  fissility.  Cleavage  is  the 
"capacity  present  in  some  rocks  to  break  in  some  directions 
more  easily  than  in  others;"  whereas  fissility  is  "a  structure  in 
rocks  by  virtue  of  which  they  are  already  separated  into  })aral- 
lel  laniiuc'D  in  a  state  of  nature."  Fissility  is  therefore  ])racti- 
cally  a  development  of  joints  on  a  very  extensive  and  closely 
set  scale,  and  chiefly  in  one  direction.  Cleavage,  on  the  other 
hand,  does  not  necessarily  imply  cavities  and  has  not  a  very 
important  bearing  on  the  present  discussion.  A  case  has  L)een 
met  in  the  granites  of  Cape  Ann,  however,  that  deserves  men- 
tion. The  granites  are  known  to  possess  a  tendency  to  split 
along  certain  plan<>s  that  greatly  facilitates  the  operations  of 
the   workmen.     K.  S.  Tarr  discovered   by  microscopic  study. 


'  ( '.    IJ.  Van  Hise,  "Principles  of  North  American  Pre-Oanibriau  Geol- 
ot^y,"    AT/  A)inual  Report  Director  U.  S.  Geological  Survey,   Part  I., 


p.  (i()H. 

"  Op.  cit.,  p.  633. 


ON  TJIK  FORMA  TWN  OF  CA  VITIES  IN  liOVKH.  16 

that  coiiicidfut  with  this  "rifting"  tliore  wan  a  niiiuito  In-occia- 
tinii  tliat  liad  no  coniurtioii  with  tho  (deavagi.'  of  tho  cotnitoiuMit 
iiiincralH  or  tiu'ir  Ijoiiiiding  HiirfacoH.  The  brticciation  lias 
iiiaiiifi'stly  rt'sultud  from  ctJinpressioii,  and  it  is  obvious  tluit  its 
proscMU'o  Tiiado  tlio  graiiito  imicli  more  ponneahlo  to  water.  A 
loi'k  of  tiiis  (4iaracter,  if  in  a  region  of  ore  deposition,  would 
•  luito  readily  become  impregnated. 

Both  Iho  joints  jmidueod  by  cooling  and  those  formod 
by  drying  and  consoiitlation  nmy  bo  afterward  modilicd 
or  increased  by  rock  movements,  and  still  ditVereut  ones  may 
be  brought  about  independently  of  eitlu-r.  Indeed,  it  is  a 
growing  belief  among  observers,  that  even  the  joints  iu  sedi- 
mentary strata,  which  have  beeu  usually  referred  to  coutrac- 
tioiial  strains  during  consolidation,  are  \\w  products  of  im'ssuro 
or  of  other  dynamical  causes,  external  to  the  rock  mass  itself. 
It  may  bo  a  very  ditHcult  matter  to  ditTerentiate  the  effect  of 
OIK'  from  that  of  the  other,  but  pressure  and  torsion  would 
naturally  occasion  displacement,  if  only  on  a  microscopic  scale. 
W.  ().  Crosby  has  suggested  the  imdulatory  tremor  of  an 
eartlitpiako  as  of  possible  importance.  Tiie  experiments  of 
Dauliiee  indicated  that  pressiu'o  woidd  produ(!e  joints,  and  that 
in  a  Imniogeneous  medium  two  sets  would  result  at  right  an- 
gles with  each  other,  and  each  at  45°  with  the  direction  of  the 
pressure.  This  theoretical  regularity  is  not  met  in  nature, 
alike  from  the  heterogeneous  character  of  rocks  and  from  the 
c()m])li'xity  of  the  strains  to  which  they  are  subject.  G.  F. 
JJccker  has  sought  in  the  several  recent  jjapers  cited  below  to 
analyze  iu  a  mathematical  way  the  theoretical  application  and 
effects  of  such  strains.  Torsional  stresses  referred  to  above 
have  beeu  suggested  as  having  im])ortaut  bearings  on  natural 
l)lieuomena,  and  esjjecially  since  the  ex])erimental  work  of 
Daulnvo  along  these  lines,  but  Becker  is  led  to  question  their 
extended  ap])lication  to  rocks. 

As  regards  the  finer  textural  characteristics  of  certain 
joint  surfaces,  J.  B.  Woodworth  has  contributed  some  very 
interesting  observations,  which,  it  is  to  be  hoped,  will  be  ex- 
tended to  a  wide  series  of  rocks.  In  certain  slaty  rocks  near 
Boston,  the  joint  surfaces  for  a  limited  area  exhibited  small 
undulations,  which  diverge  from  a  central  axis,  like  the 
branches  of  a  feather,  but  which  then  bend  in  curved  surfaces 


16 


KEMP'S  CRK  DEPOSITS. 


:1    I' 


of  naucb  larger  development,  so  as  to  form  somewhat  exteiuled 
cornif^atioiis.  The  author  remarks  the  resembhiuce  which 
the  distribution  of  certain  great  fractures  in  the  earth's  crust 
bears  to  these  liand  specimens,  a  suggestion  that  might  be  tested 
in  fractured  areas  containing  veins. 

It  is  manifest  that  the  passage  from  joints,  pro})erly  speaking, 
and  as  outlined  above,  to  slaty  cleavage,  schistosity  and  dy- 
namic effects,  that  are  the  residts  of  many  small  fractures  and 
shearing  surfaces,  is  a  gradual  one.  and  that  the  two  are  inti- 
mately connected.  Tlio  references  below,  therefore,  embrace 
both,  although  schistosity  is  but  briefly  referred  to  here,  as  its 
connection  is  not  particularly  close  with  the  origin  of  ore 
bodies,  however  much  it  may  afterward  affect  them.' 

1.0*^.0:5.  Cavities  Formed  bij  More  Extensive  Movements 
in  the  K(irth\s  Crust. — The  strains  produced  by  comjn-ession 
in  the  outer  portion  of  the  earth  are  by  far  the  most  ini})ortant 
causes  of  fractures.  The  compression  develops  a  tangential 
stress  which  is  resisted  by  the  archlike  disposition  of  the  crust, 
(By  the  term  "crust"  is  simply  meant  the  outer  portion  of  the 


1  fi.  F.  Becker  on  the  proiluctiou  of  fissures.  See  paper  on  "  Tlie  Struc- 
ture of  a  Portion  of  the  Sierra  Nevada  of  California,"  BiiUctui  Geolugieal 
Societjf  oj  ^lHiem*a,  II.  4!»,  1891 ;  .also  "Finite  Homogenous  Strain,  Flow 
and  Rupture  uf  Roc-ks," /*»(.,  IV.  i:5.  1898;  "The  Finite  Ehiftic  Stress- 
strain  Function."  Aiiwr.  Jour.  Svi..  Nov.,  1893,  p.  3:57.  The  above  are 
ratlier  mathematical  for  the  general  reader  and  the  following  are  le.ss  so. 
"The  Torsional  Theory  of  Joints,"  Tnim.  Auier.  Inst.  Min.  Eiig.,  XXIV. 
130,  1894;  "Schistosity  and  Slaty  Cleavage,"  Joxnial  of  Gcologn.  IV.  429, 
189(1;  "Recounoissance  of  theCJold  J'"ields  of  the  Southern  Api)alachians," 
XVI  Aim.  Ri-p.  Dii:  U.  S.  Geo!.  Surveif,  Part  III.,  SB-V^T^;  W.  C. 
Croshy,  "Absence  of  the  Joint  Structure  at  (ireat  !)ei)ths,"  GcdI.  Maija- 
ziiic,  Sept.,  1881,  p.  4i<);  "Classilication  and  Origin  of  Joint  Structure.s," 
Proc.  Boston  Soc.  Nat.  Hist.,  XXII.  72,  1882;  "On  the  Joint  Structure  of 
Rocks,"  Tcclnwiog)/  Qiiartci-lif.  lS!t(»;  "The  Origin  of  Parallel  and  Inter- 
secting Joints,  Jdiiii.,  VI.  2;!((,  1893;  also  in  Aiiicr.  Gcologi.st,  Dec,  1893, 
368;  (}.  K.  Gilbert,  "On  the  Origin  cf  Jointed  Stni"ture,"  Anicr.  Jour. 
.SV('.,  July,  1882,50;  J.  Le  Conte,  "  Origin  of  Jointed  Structure  in  Undis- 
turbed Clay  and  Alarl  Deposits,"  Ainer.  Jour.  Sci,  III.,  xxiii.  233;  W.  J. 
McGee,  "  On  Jointed  Structure,"  Avicr.  Jonr.  Soi.,  III.  xxv.  1.')2,  47(>. 

An  excellent  bibliograjiby  on  slaty  cleavage  ui)to188.-)  will  Ik-  fovnidin  a 
])aper  by  Alfn  1  Darker,  in  licp.  liritinh  Axkoc.  for  the  Adnn.rcinciit  of 
Sviciic)',  18S,5,  S|3,  and  upon  this  ami  other  kindred  subjects,  Daubree's 
Etudes  Syntheticiues  de  (leologie  p]xperimeutale,  1879,  Part  I, ;  Sub  Part 
II.,  Chaps.  I.-IV. 


ON  THE  FOIUIATIOX  OF  ('AVITIKS  IX  JIOCKS. 


ir 


l^lolie  without  reference  to  the  character  of  the  interior. )  Whore 
there  is  insufficient  support,  gravity  causes  a  sagging  of  tlie 
material  into  synclinals,  which  leave  salient  anticlinals  be- 
tween them.  Where  the  tangential  strain  is  also  greater  than 
the  ability  of  the  rocks  to  resist,  they  are  upset  and  crumpled 
into  folds  from  the  thrust.  Both  kinus  of  folds  are  fruitful 
causes  of  fissures,  cracks,  a  <  general  shattering,  and  every  slip 
from  yielding  seiids  its  oscillations  abroad,  which  cause  breaks 
along  all  lines  of  weakness.  The  simplest  result,  either  from 
sai;';j,iug  or  from  thrust,  is  a  fissure,  on  one  of  whose  sides  the 
wall  has  dropped,  or  on  the  other  of  which  it  has  risen,  or  both, 
as  will  be  more  fully  described  luider  *'Faults."  If  the  rocks 
are  firm  and  quite  thickl}^  bedded,  as  is  the  case  with  lime- 
stones and  quartzites,  the  separation  is  cleanly  cut ;  but  if  they 
Mre  softer  and  more  yielding,  they  are  sheared  downward  on 
tlie  stationary  or  lifting  side,  and  upward  on  the  one  which 
relatively  sinks.  Such  fissures  may  pass  into  folds  along 
their  strike,  as  at  Leadville,  Colo. 

1.0-?. (H.  A  phenomenon  which  is  especially  well  recognized 
in  metamorphic  regions,  and  which  is  analogous  to  those  last 
cited,  is  furnished  by  the  so-called  "shear  zones,"  A  faulting 
movement,  or  a  crush,  may  be  made  ajjpareut  in  rocks  of  this 
cliaracter  by  changes  in  mineralogical  composition  and  structure, 
as  well  as  by  clearly  fr:  .ctured  rocks.  Massive  diabases,  for  in- 
stance, })as8  into  hornblende  schists  or  amphibolites  for  limited 
stretches.  Garnets  and  other  characteristically  metamorphic 
minerals  appear,  and  pyroxenes  alter  to  amphi boles.  Strains 
are  manifested  in  the  optical  behavior  of  the  minerals  in  thin 
sections  of  specimens  taken  from  such  localities.  These 
crushed  strips,  or  shear  zones,  may  be  formed  with  very  slight 
displacement,  but  they  afford  favorable  surroundings  for  the 
formation  of  ore  bodies.  This  conception  of  the  original  condi- 
tion of  a  line  of  ore  deposition  is  a  growing  favorite  Avith 
recent  writers,  and  ccmibined  with  the  idea  of  replacement  is 
often  api)licable.  Fablbands,  wdiicli  are  very  puzzling  prob- 
lems, may  have  originated  as  shear  zones. 

1. ••■-*. 05.  A  more  extended  effect  is  produced  by  the  mono- 
cline, Avbich  has  a  double  line  of  shattered  rock  marking  both 
the  crest  and  foot  of  its  terrace.  Anticlines  and  synclines 
occasion    the  greatest    disturbances.     Comparatively     brittle 


18 


KEMP'S  ORE  DEPOSITS. 


materials  like  rocka  cannot  endure  bending  without  suffering: 
extended  fractures.  When  strained  beyond  tbeir  limit  of  resist- 
ance, along  tbeci'ostof  an  anticline,  and  in  the  trough  of  a  syii- 
cline,  cracks  and  fractures  are  formed  which  radiate  from  tlic 
axis  of  each  fold.  As  these  open  upward  and  outward  in  anti- 
clines, they  become  the  easiest  points  of  attack  for  erosion,  .s<i 
that  it  is  a  very  common  thing  to  find  a  stream  flowing  in  a 
gorge,  which  marks  the  crest  of  an  anticline,  while  synclinal 
basins  are  frequently  left  to  form  the  sunnnits  of  ridges,  as  is 
so  markedly  the  case  in  the  semi-bituminous  coal  basins  of 
Pennsylvania.  It  is  quite  probable,  howovei*,  tb.at  the  anti- 
cline may  have  been  leveled  off  at  this  fissured  crest  because  it 
was  upheaved  under  water  and  became  exposed  at  its  vulner- 
able summit  to  Avave  action. 

Ore  deposits  may  collect  in  these  fissured  strips,  of  which  t'nc 
lead  and  zinc  mines  of  the  upper  IMississippi  Valley  (Example 
24)  are  illustrations.  Such  fissures  are  peculiar  in  that  they 
exhibit  no  displacement.  The  accompanying  figure  is  from  a 
photogr;),ph  of  a  gaping  crack  in  the  Aubrey  (Ujiper  Carbonif- 
erous) limestone,  twenty-five  miles  north  of  Canon  Diablo  sta- 
tion, Ariz.,  on  the  Atlantic  and  Pacific  Railroad.  It  was 
caused  by  a  low  anticlinal  roll  and  contained  water  about  one 
himdred  feet  below  the  top.  Its  reproductions  of  the  condi- 
tions of  a  vein,  with  horse,  pinches  and  swells,  devious  course. 
and  all,  is  striking.  The  photograph  was  made  by  Mr.  G.  K. 
Gilbert,  of  the  United  States  Geological  Survey,  and  to  his 
com'tesy  its  use  is  due. 

While  it  is  true  that  in  many  regions  the  folds  and  fractures 
have  resulted  in  this  simjjle  way,  and  exhibit  the  unmistaka- 
ble coiu'se  througii  which  they  have  passed,  yet  geological 
structure  is  by  no  means  always  so  clear.  Extended  disturb 
ances,  great  faults  and  disjilacements,  combiiu'd  with  folds 
and  the  intrusion  of  igneous  rocks,  have  often  so  broken  up  a  dis- 
trict that  it  is  a  matter  of  much  difficulty  to  trace  out  the 
course  through  which  it  has  passed,  Subsecjuent  erosion,  or 
the  superposition  of  heavy  beds  of  gravel  or  forest  growtlis. 
etc.,  may  so  obstruct  observation  even  of  the  facts  as  to  add  to 
the  ol)scurity.  The  expense  of  making  and  the  consequent 
scarcity  of  accurate  contour  majts  to  assist  in  such  work  arc 
other  obstacles.     The  profound  dynamic  effects  wrought   b\ 


:?!,"* 


t  suffering' 

it  of  resist- 

h  of  a  Byii- 

3  from  till' 

ird  in  anti- 

erosion,  8(1 

awing  in  a 

e  synclinal 

(Igos,  as  is 

basins  of 

t  tlie  anti- 

;  because  it 

its  vulner- 

wbich  t'lic 

IF 

(Exanij)lo 

tbat  they         ', 

i  is  from  a 

•  Carbon  if-        ,' 

Diablo  sta-        4 

1.     It   was 

•  about  one 

tbo  condi-         > 

)ns  course.         f 

Mr.  G.  K. 

,ud   to  bis        -i 

1  fractiu'es          " 

iinnistaka-        ''% 

geological         i 

'd  disturb          '$. 

vith    folds          ;| 

1  up  a  dis-        71 

■e  out   tilt'          f 

.erosion,  nr          j 
growths.          1 

i  to  add  t" 

onsequeiii          y| 

1  Avork  ait'         .4 
•ought   1»\         -4 

.■*a;.33E:-.«i 


Vu;   '2.—<>iir  I  JhxKfv  ill  till'  AKhirif  Uiiirsfoiic   (I'jijH'r  C'tirhoniffroiis) 
inih':,  ii!rt]i  of  Ciirioii  Dinblii  Stdlinii.  Ariz.,  on  flic  A.  d!-  /'.  li.  R. 
Reproduced  from  <i  photoifrnph  hif  (1.  K.  (iilbcrf,  18!)3. 
{Scii'iicc,  AiNjiisf '2,  IS!).-),  IIS.) 


moi 
due 
eval 

stlK 
CUIU 

thai 
abu: 
alor 
and 
are 
The 
1. 
port 
fanl 
wes 
line 

COV( 

dow 
witl 
sma 
plet( 
(See 
III. 
tied 
1. 
tioni 
rest) 
sliee 
Fok 
sliat 
[and 
8  lire 
vert 
Snc'l 
eacli 


(lU;il 
sure 

^<)i"  Q. 

[SO  a 


ON  TllK  FORMATION  OF  CA  ]IT1FS  IN  HOCKS. 


19 


inouutHin-making  })r()Ct'sses,  although  in  individual  cases  pnj- 
(hiciug  only  the  simpler  phenomena  already  cited,  yet  in  gen- 
eral are  much  more  extensive,  and  must  be  considered  in  the 
study  of  many  large  districts.  When  folds  are  the  result  of 
comjjressiou  or  thrust,  the  dynamic  eft'ects  are  more  marked 
than  in  those  formed  by  sagging.  Faults  are  larger  and  more 
abundant.  When  sedimentary  beds  have  been  laid  down 
along  an  older  axis  of  granite  or  some  e(iually  resistant  rock 
and  the  thrust  crowds  the  beds  against  this  axis,  the  conditions 
are  eminentlj'  favorable  t(j  great  fracturing  and  disturbance. 
The  tianks  of  the  Rocky  Mountains  furnish  such  examples. 

l.O'^.OO.  There  are  also  great  lines  of  weakness  in  the  outer 
portion  of  the  earth,  which  seem  to  have  been  the  scene  of 
faulting  movements  from  a  very  earlj'  period.  Thus,  on  the 
western  front  of  the  Wasatch  Mountains,  in  Utah,  is  a  great 
line  of  weakness,  that  was  first  faulted,  as  nearly  as  we  can  dis- 
cover, in  Archean  times,  and  has  suffered  disturbances  even 
down  to  the  present.  A  few  instances  of  actual  movements 
within  recent  years  have  been  recorded.  In  1889  a  sudden 
small  fold  and  fissure  developed  under  a  paper  mill  near  Ap- 
pleton.  Wis.,  and  heaved  the  building  four  and  a  half  inches. 
(See  F.  Cramer,  "Recent  Rock  Flexm-e."  Anicr.  Jour.  .SV/., 
III.,  xxxix.  220.)  This  occurred  in  what  was  regarded  a  set- 
tled region,  and  one  nt)t  liable  to  disturbance. 

1.02.07.  Wherever  igneous  rocks  form  relatively  large  por- 
tions of  the  globe  they  necessarily  share  extensively  in  ter- 
restrial disturbances.  Not  being  often  in  sufficiently  thin 
sheets,  they  rarely  furnish  the  phenomena  of  dip  and  strike. 
Fiilds  are  largely  wanting.  They  are  replaced  by  faults  and 
shattering.  The  fissures  thus  formed  are  at  times  of  great  size 
and  indicate  important  movements.  The  Comstock  Lode  fis- 
'sure  is  four  miles  long  and    in    the    central  part  exhibits  a 

vertical  displacement  of  three  thousand  feet.  (See  2.11.'^M.) 
Such  fissiires  seldom  occur  alnne,  but  minor  ones  are  found  on 
^eacli  side  and  i)arallel  Avith  the  main  one. 

1.02.08.  The  intrusion  of  igneous  dikes  may  start  earth- 
(luake  vibrations  which  fracture  the  firm  rock  masses.  Fis- 
sures caused  in  this  way  radiate  from  the  center  of  disturbance 
|or  else  appear  in  concentric  rings.  The  violent  shakings  which 
[no  often  attend  great  volcanic  eruptions,   and  the  sinking  of 


20 


KEMP'S  ORE  DEPOSITS. 


the  Hurface  from  the  removal  of  underlying  molten  material, 
all  tend  to  form  cracks  and  cavities.  They  are  possible  causes 
which  may  well  be  borne  in  mind  in  the  study  of  an  igneous 
district. 

1.02.01).  Faults. — When  fractures  have  been  formed  by 
any  of  the  means  referred  to  above,  and  the  opposite  walls  slip 
past  each  other,  so  as  not  to  correspond  exactly  at  all  horizons, 
they  are  called  "faults,"  a  term  which  indicates  this  lack  of 
correspondence. 

The  separation  is  chiefly  due  to  the  relative  slipping  down 
or  sinking  of  one  side.  The  distance  through  which  this  has 
taken  place  is  called  the  amount  of  displacement,  or  throw. 


{■:■■■*'.■:■<(■  ::W' 


I.  •.■..•■••.  'x  ■■■..*;■.. :  'UV  • ;  ,'v//, 
•*-;.'-~-V..-;:.-v.i^'\,'V.-.x 


;■^^•••.:v.:•.•x:•:;».•.•:x.•.:;:;;;.v."•••« 


C, .  •  •  . .  ^\.\ , .//.  ^^/^,  .•»  .••.  .'*,  .•  •,\»  •• .  .•. 
<  ?.•;■:.  •;;;•.  •.  •  ;•  •;•.■  ft  •  x--  .^c  •.•  r,-  .• 

I  .■•■«;■.■.« •■.■•X  •■  •■.r»1  •.••■•.■■.•';".■  »'•■•■•« 
oJ.:-^v-.^:":'.;>nx"' •'<■.•:■.*••■■.■: 

£  *.    •  • .  X  ■ '   .  X  •  •  .  *^^ •  w       '^ 

«■"•"..*■■.■.••••'.•  '•  ;•■  •■'.^•■.•'x  •'.•"'■".•:!: 

..•••••■•.     ...  •  X  •  \^  '    .  •     .  •       •  •  .       . 


•■*.:'■'.■ 


*':■■  X 


;;;.-?<-.-^v;?.-:;-::-v-;Vx-,:-;«v-'J 

;,::-x-.vx. ■■■.«■:;•.. :^^^^n::x 


viij^  ;V :  X  ■  v';  V  ■  V  ■•  v;;.v,:.v  >  lyv-^vlv; 


Fia.  3.— Normal  fault,  Leadvillc,  Colo.     After  A.  A.  Bloiv. 

Faults  are  most  commonly  inclined  to  the  horizon,  so  that 
there  is  botli  a  vertical  and  a  horizontal  displacement.  The  in- 
clination of  a  fault  plane  to  the  horizontal  is  called  the  dip, 
just  as  in  the  case  of  stratified  rocks.  Its  inclination  to  the 
vertical  is  the  hade.  Faults  most  commonly  run  parallel  with 
the  strike  of  inclined  rocks,  and  are  then  called  "strike- faults." 
When  they  cut  across  the  strike  and  are  in  the  direction  of  the 
dip  they  are  called  "dip-faults."     Experience  lias  shown  that 


ON  Till!:  FOIIMATION  OF  CAVITIES  IN  RUCKS. 


21 


where  beds  or  veins  encounter  faults  and  operations  aro  brou^lit 
to  H  standstill,  the  continuation  is  usually  found  as  follows, 
according  to  Schmidt's  law.  If  the  fault  dips  or  hades  away 
from  the  workings,  the  continuation  is  down  the  hade;  if  it 
dips  toward  the  workings,  it  should  ho  followed  upward.  Such 
a  fault  is  called  a  normal,  or  gravity  fault,  and  is  illustrated  iu 
the  figure  on  p.  '^0,  after  A.  A.  Blow.  This  is  a  natural  result 
of  the  drawing  apart  of  the  two  sides.  The  least  supported 
mass  would  slip  down  on  tlio  one  which  has  the  larger  base. 
Less  commonly  the  opposite  movement  results.  Thus,  when 
the  fault  is  due  to  compression,  the  beds  pass  each  other  in  the 
reverse  direction,  and  what  is  called  a  reverse  fault  results. 
The  accompanying  cut  illustrates  a  very  extended  one  in  the 


SECTION  f. 


^:::^^=^=;^:^i>C>^^^~^^^S^^  Coimasauga  S/ialeS 


^^i^^^^[T|2   Cohatta  Conijlonieixite' 

SS^Si      Ocoee  Slate 

Knox  Dolomite 


Fig.  4.    Reversed  Fault  at  Hollii  Creek,  near  Dalton,    Qa.      After  C.  W. 
Hayes,  Bull.  G.  S.  xl.,  Vul.  IT..  Pi  J,  p.  15:2 

southern  Appalacliians.  While  we  would  naturally  think  of  a 
reversed  faidt  as  residting  from  a  compressive  strain,  in  that  in 
this  case  the  lower  wedge-shaped  portion  woald  be  forced 
under  the  upper  one,  yet  normal  faidts  can  likewise,  in  in- 
stances, be  explained  by  compression.  If  we  consider  the  fault 
to  be  caused  by  the  vertical  thrust  or  component,  that  would  al- 
ways be  present  iu  the  compression  of  a  com})letely  supported 
arch,  this  would  tend  to  heave  upward  the  portion  next  the 
fissure  that  had  the  larger  base.  Along  an  inclined  fracture 
such  portion  is  manifestly  the  under  one.  Again,  if  the  com- 
pressive strain  is  applied  in  a  direction  parallel  with  the 
fissure,  and  not  ;it  right  angles  to  it,  the  hanging  wall  might 
be  forced  to  bulge  downward  and  the  footwall  upward,  thus 


22 


KK.VP'S  ORE  DEPOSITS. 


yieldiii{<  a  normal  fault  by  conijn'ession.  It  is  important  t(j 
note  whether  tlio  fault  plane,  both  in  normal  and  in  reversed 
faults,  outs  inclined  beds  in  the  direction  of  the  dip  or  across 
it,  because  the  relative  amount  of  vertical  and  lateral  displace- 
ment is  much  affected  by  these  considerations.  (See  Margerie 
and  Heim,  Dislohitioii.  dcr  I^Ji-driiidc,  Zin-ich,  IKSS.) 

l.OvMO.  The  movement  of  the  walls  on  each  other  produces 
grooves  and  polished  surfaces  called  slickensides,  or  slips. 
They  are  iisually  covered  with  a  layer  of  serpentine,  talc,  or 
some  such  secondary  product.  The  strain  caused  by  the  move- 
ment may  in  rare  instances  leave  the  sli{)3  in  such  a  state  of 
tension  that  when,  from  any  cause,  such  as  excavation,  the 
pressure  is  relieved,  tliey  will  scale  off  with  a  small  explosion.' 
Observations  on  the  directions  of  slips  may,  in  cases  of  doubt, 
throw  some  additional  light  on  the  direction  of  the  movement 
which  occasioned  the  fault.  Some  particular  and  recognizable 
bed  or  vein  niay  be  crushed  and  dragged  down  by  the  faulting 
movement,  and  afford  the  so-cnlled  "trail  of  the  fault,"  which 
will  indicate  the  direction  of  movement  and  direct  the  miner. 
But  the  best  guide  in  stratified  rocks  is  a  knowledge  of  the  suc- 
cession of  the  beds  as  revealed  by  drill  cores  or  excavations. 
Attempts  have  been  made  to  deduce  mathematical  formulas 
for  the  calculation  of  the  amount  of  downthrow  or  upthrow, 
and  when  sufficient  data  are  available,  as  is  often  the  case  in 
coal  seams,  this  may  be  done.  The  methods  depend  on  the 
projection  of  the  planes  in  a  drawing,  on  the  principles  of  ana- 
Ij'tical  geometry,  and  on  the  calculation  of  the  displacements  bj' 
means  of  splierical  trigonometry.^  Prof.  Hans  Hoefer  has 
called  attention  to  the  fact  that  in  faulting  there  is  frequently  a 
greater  displacement  in  one  por*^ion  of  the  fissure  than  in  a 
neighboring  part,  and  even  a  difference  of  hade.  This  causes 
a  twisting,  or  circular  movement  of  one  wall  on  the  other,  and 


*  See  A.  Strahan,  "On  Explosive  Slickensides,"  Geological  Magazine, 
IV.  401,  523. 

-'  See  (j.  Koehler,  Die  Stonmgen  der  Gunge,  Flotze  and  Lager,  Leipzig, 
1886;  William  Englemann.  A  translation  by  W.  B.  Phillips,  entitled,  "Ir- 
regularities of  Lodes,  Veins  and  Beds,"  appeared  in  the  Engineering  and 
Mining  Journal,  June  2"),  1887,  p.  454,  and  July  2,  1887,  p.  4.  A  very  ex- 
cellent paper,  having  a  (luite  complete  bibliography,  is  F.  T.  Freeland's 
"Fault  Rules,"  Trans.  Amer.  Inst.  Min.  Eng.,  XXI.  491,  1892. 


ON  THE  FORMA  TION  OF  CA  Vri'lKti  IN  HOCKS. 


23 


needs  to  be  allowed  for  in  soniecalculatioiiH.'  In  the  Engineer- 
i ml  and  Minimj  Jonrnal  for  April  and  Ma}',  ]8i»"^,  a  quite 
extendcnl  diHCUssion  of  faults  by  several  prominent  American 
iniiiinfj^  engineers  and  geologists  is  given,  apropros  of  the  (jues- 
tion  raised  by  Mr.  J.  A.  Church  as  to  whether  fissure  veins 
are  more  regular  on  the  dip  or  on  the  strike.  In  a  roiaiively 
uiiit'orm  massive  rock  the  regularity  should  be  gre'vter  on  the 
di}),  but  in  inclined  and  diversified  stratified  rocks  too  many 
variables  enter  to  warrant  any  sweeping  assevtions.  In  soft 
rocks  like  shales  the  fissure  may  become  so  split  into  saiall 
stringers  as  to  bo  valueless.  Again,  in  very  firm  rock,  where 
there  is  little   drawing  apart,  the  fissure  may  be  very   tight. 


Fig.  T).  nimtration  of  an  older  vein,  the  Jumbo,  faulted  by  a  later  one, 

(cross-vcui)  at  Ak'WiiKm  Hill,  near  Rico,  Colo.      After  T.    A. 

Riekard,  Trans.  Amer.  Inst.  Min.  Eng. 

In  the  veins  of  Newman  Hill,  near  Rico,  Colo,  (see  2.00.11), 
tiio  fissure  is  so  narrow  above  a  certain  statum  as  practically  to 
fail.  Quartzite  is  a  favorable  rock  for  such  effect.  Despite 
all  rules,  faults  are  often  causes  of  great  uncertainty,  annoy- 
ance, and  expensive  exploration. 

l.O'Ml.  If  a  number  of  faults  succeed  one  another  in  a 
short  distance,  they  are  called  "step  faults."  An  older  and 
completed  vein  may  also  be  faulted  by  one  formed  and  filled 
later.  In  such  a  case  the  continuous  one  is  the  younger. 
Figure  5  above  will  illustrate  each  case.  At  the  intersection 
of  the  two,  the  later  vein  is  often  richer  than  in  other  parts. 

1.03. 12.  If  a  faulted  series  of  rocks  is  afterward  tilted  and 
eroded,  so  as  to  expose  a  horizontal  section  across  the  strike  of 
the  faulting  plane,  an  apparent  horizontal  fault  may  result;  or 

'  Oesterreiclie.i  Zeitschrift  fi'tr  Berg-vnd  Hfdfenire.'ien.Ydl.XXTX.  An 
abstract  in  Englisli  is  given  by  R.  W.  Raymond,  Trans.  Amcr.  Inst.  Min. 
Eng.,  X.  456,  1SS3. 


34  KEMP'S  Oll/'J  DEPOSITS. 

if  tlie  erosion  succeeds  normal  faulting  and  lays  bare  two  un- 
confonnablu  beds  each  side  of  the  fissure,  a  lack  of  correspond- 
ence in  plan  as  well  as  in  section  may  be  seen.  Faulting  frac- 
tures are  seldom  straight:  on  the  contrary,  the.y  bend  and  cor- 
rugate. When  the  walls  slip  jtast  each  otluu*.  tlu^y  often  st()]> 
with  projection  opposite  projection,  and  depression  op|iosito 
depression.  These  irregidarities  cause  pinches  and  swells  in 
the  resulting  cavity,  and  constitute  one  of  the  connnonest  phe- 
nomena of  veins.  Fissures  also  gradually  pinch  out  at  their 
extremities,  or  break  uj)  into  various  ramifications  diat  finally 
entirely  cease.  They  may  pass  into  folds,  as  stated  above.  It  is 
not  surprising,  therefore,  that  in  stratilied  rofks,  the  largest 
faults,  as  a  matter  of  observation,  are  usually  jiaralld  with  the 
general  strike.  They  cross  the  strike  or  run  in  the  sense  of  the 
dip  much  less  fre(iuently. 

1.0"i.l3.  Zones  of  Possible  Fracture  in  the  E(irfh\s  Crust, 
— In  a  discussion  of  the  deformation  of  rocks  C.  R.  Van  Hise' 
has  recently  established  the  conception  of  three  zones  in  the 
earth's  crust,  which  are  intimately  connected  in  a  large  way 
with  the  subjects  just  discussed.  They  are  (1)  an  upper  zone 
of  fracture;  {'i)  a  middle  zone  of  combined  fracture  and  plas- 
ticity; {'■])  a  lower  zone  of  plasticity.  (1)  Rocks  under  less 
weight  than  their  ultimate  strength,  when  rapidly  deformed. 
ai'e  iu  the  zone  of  fracture.  This  is  manifestly  incontroverti- 
ble and  the  conception  adds  to  the  points  touched  on  in  preced- 
ing paragraphs  the  important  further  one  of  the  load  imder 
which  the  rocks  stand  at  the  time  of  experiencing  the  strain. 
As  already  pointed  out,  the  character  of  the  wall  rock  will 
influence  the  resulting  fissure,  firm  rocks  giving  clean-cut 
fissures,  while  soft  rocks,  such  as  shales,  will  more  readily 
break  along  nmltitvides  of  small  cracks.  The  amount  of  loa<l  is 
also  important,  for  with  its  increase  even  the  firmest  rock 
could  not  fracture,  as  is  shown  in  describing  the  next  two 
zones.  It  is  also  manifest  that  the  depths  of  the  zones  are  vari- 
able in  different  regions,  on  account  of  local  differences  of 
rocks,  and  that  thejare  not  to  be  too  sharply  viewed  iu  a  quan- 
titative way. 


'  Princijiles  of  North  Aniericiui  Pre  Camhrian  (ieolojjy,  XVI.  Annual 
E('l>  Dir  U.  S  Gcol.  Snrrcij,  Purt  I  ,  58i),  ISiJCI.  See  also  Journal  uf 
Geology,  IV.  195,  312,  449,  593. 


ON  THE  FORMATION  OF  CA  VITIES  IN  liOCh'S. 


25 


In  round  niunbors  the  miixinium  depths  at  ^vllich  cjivities 
can  exist  varies  from  500  meters  (1,025  ft.)  for  nott  shaU'S  to 
10,000  meters  (.'5 •^,500  ft. )  for  firm  granites.  Those  maximum 
dejiths  introduce  zon(^  (.'!),  orthezoneof  flowage,  \vht'r(>inthe  h)ad 
is  so  excessive  that  the  yielding  to  deformation  comes  in  the  way 
of  a  viscous  How,  or  plastic  yielding,  evidences  of  which  are 
visible  in  many  gneisses.  That  such  a  zone  exists  will  appear 
to  any  one  who  retiects  upon  the  necessary  behavior  and  yield- 
ing of  rocks,  which  are  confined  on  all  sides  and  yet  are  com- 
pressed beyond  their  limits  of  resistance.  The  second  or  inter- 
mediate zone  embraces  the  lua-dcr  region  between  (1)  and  (;}), 
or  the  region  of  combined  fracture  and  tlowage. 

These  considerations  have  an  important  bearing  on  the  forma- 
tion of  veins,  because  they  indicate  that  veins  nuist  be  limited 
to  the  outer  jjortions  of  the  globe  and  nuist  have  always  formed 
in  such  smroundings.  The  considerations  as  regards  their 
practical  bearing  are  largely  theoretical,  it  nuist  be  admitted, 
because  even  moderate  estimates  of  the  depth  of  zone  (1 )  soon 
rea(!h  helow  the  limit  of  possible  mining,'  but  in  their  broad 
scientific  bearings  they  are  a  valuable  aid  to  the  formation  of 
correct  views  on  the  necessary  place  of  origin  of  veins.  The 
"ewige  Teufe"  of  the  earlier  miners  is  therefore  (juite  limited. 

1.0'M4.  Secoixhiri/  Modijicdfioiis  of  ( 'arilics. — Fractures 
and  cavities  of  all  sorts  speedily  become  lines  of  subterranean 
drainage.  The  dissolving  power  of  water,  and  to  a  much 
smaller  degree  its  eroding  jiower,  serve  to  modify  the  walls 
very  greatly.  An  enlargement  may  result,  and  what  was  per- 
hn])s  a  small  joint  or  fissure  may  become  a  waterwa}'  of  con- 
siderable size.  This  is  especially  true  in  limestones,  in  which 
great  caverns  (like  the  Mammoth  Cave  and  Luray's  Cave)  are 
excavated.  Caves  are,  however,  almost  always  due  to  surface 
water,  and  do  not  extend  below  the  permanent  water  level  un- 
less they  have  been  depressed  aftev  their  formation." 

1.0:i.l5.  The  subterranean  movements  of  Avater  are  of  ])rime 
niiportauce  in  connection  with  so  many  aspects  of  the  subject 
<if  (jre  deposits  that  it  is  necessary  to  have  a  fairly  definite  con- 


I 


'  See  in  this  coimeetiou  A.  C.  Laue,  "How  Deep  Can  we  Jline?"  The 
Minrral  Indnsir!/,  IV.  7(57.  10,000  ft.  is  placed  as  a  geueral  limit,  with 
possibilities  as  far  as  15,000,  but  probably  not  miicli  beyoud. 

■  See  J.  S.  Curtis,  Monogniph  VII.,  C  S.  (leal.  Siwvey,  Chap.  VIII. 


aG 


KEMl'S  OIIK  DKl'OSirs. 


coption  of  their  natiiro  aud  cuiiHes.  Wiitor  fulling  on  tlio  Hur- 
faco  HS  raiu  iu  part  riniH  oil'  at  once,  in  part  evaporatcH,  at  iojist 
hoforo  it  lias  gouo  far,  and  iu  part  Hinks  into  tlio  ground. 
VV  itli  tlu)  last  nanuMl  wo  aro  esjitMMally  ooncornod.  World-wide 
oxporioiu'o  long  ago  doniouHtratod  tliat  under  all  portit)nH  of 
tho  land,  uuIosh  jJosHildy  in  excossivoly  arid  and  oxcoptioual 
diHtricts,  tliero  is  a  body  of  almost  stationary  wator,  that  main- 
tains a  very  constant  lovel  and  that  will  till  a  w  "one  is 
sunk  sufHciontly  deep.  Where  the  rainfall  ia  heav  .ns  "per- 
manent water  level"  or  "ground  water"  stands  only  a  short 
distanee  helovv  tho  surface,  it  may  be  only  a  few  feet;  but  in 
regions  of  slight  rainfall,  it  is  correspondingly  depressed.  It 
varies  also,  more  or  less,  with  tho  nature  of  the  local  rocks, 
with  the  nearness  or  ren)oteueH8  of  low -lying  valleys  and  with 
the  geological  structure.'  The  "ground  water"  that  stands  at 
this  level  is  to  bo  distinguished  from  the  actively  circulating 
water  above  it — the  "vadose"  circulation  of  Posepny,"  whose 
recent  treatise  has  served  to  focus  attention  upon  this  phase  of 
the  subject — and  is  not  itself  without  motion,  because  where  it 
is  sitijated  above  some  more  or  less  remote  and  lower  lying 
outlet  it  passes  toward  it  by  a  slow,  gradual  fl'-  or  sinks 
downward,  moves  laterally  and  rises  again  by  a  ^nic  ac- 

tion. Cracks  and  clefts  are  the  cliief  lines  of  movement  in 
both  these  circulations,  and  instances  are  known  of  communi- 
cations across  wide  intervals.  Capillary  circulations  are  also 
not  lacking  but  are  of  less  quantitative  moment.  As  solvents  of 
rocks  the  ground- water  circulations 'are  not  comparable  witbthe 
vadose,  for,  as  already  remarked,  caves,  the  chief  results  of 
such  solution  and  removal,  are  essentially  products  of  the 
latter. 

1.02.  in.  The  ground-water  stands  between  the  motive  power 
of  the  overlying  hj'drostatic  column  and  the  further  motive 
power  of  the  underlying  heated  zones  of  the  earth,  to  which 
some  of  the  surface  water  attains,  more  or  less  by  capillary 
movements,     l^aubree  has  shown  that  capillary  attraction  is 

'  See,  in  this  connection,  T.  C.  Clianiberlin,  "Tlie  Reiinisite  and  Qualify- 
ing Conditions  of  Artesian  Wells,"  Fij'tli  Annual  Hep.  Dir.  U.  8.  Geul. 
Survey,  131,  ISH.'). 

*  Transact ionH  Amrr.  Inst.  Min.  Eng.,  XXIII.  211?,  1S1)8.  Reissued  as 
"Genesis  of  Ore  Deposits,"  in  which  see  p,  17. 


ON  TIIK  /<'()/!. \f.\r/(t.\  OF  lAVrrih'S  IN  UOCKS. 


27 


i'lVcctive  oven  agaiuHt  ntcam  pivsHuro.'  Coolinf^  but  Htill 
hoitiHl  intruHiouH  of  igueoun  rockn,  wliicli  may  not  necesHaril}' 
reach  tho  surfaco,  are  douhtU'HH  tlio  niont  stu-iouH  of  all  tlicHe 
iiiti'i'iial  Htiiimlators.  and  furnish  uh  w  ith  tho  most  rcasonahlo 
causii  for  thoao  activo  circuhitiijUH,  that  liavu  led  to  oro-dopiwi- 
tion  in  regions  of  extended  mineral  voiiiH,  Tliey  are  at  once 
locali/ed,  of  relatively  abrupt  development,  atid  they  bi-ing 
j^'reat  Htorew  of  heat  within  the  conceivable  zonen  of  the  ground- 
water's existence.  It  ia  also  (juite  probable  that  waters  and 
other  fluid  or  vaporous  substances  are  emitted  and  tlriven  out- 
Avard,  which  are  not  derived  from  infiltrations  from  the  surface, 
l)ut  which  have  been  involved  in  the  substance  of  igneous  mag- 
mas since  their  derivation  from  the  original  nebula.  All  these 
circulations  from  deep-seated  sources  are  more  likely  to  be 
fillers  than  enlargers  of  cavities  in  the  upper  jwrtions  of  the 
zone  of  fracture. 

It  is  conceivable  that  the  heat  necessarily  developed  in  tho 
crushing  and  fractme  of  rocks  on  a  large  scale  may  also  he  an 
important  local  stinudus  and  in  this  way  contribute  in  no  small 
degree  to  the  final  results. 

l.0'^.17.  The  solvent  action  of  water  is  vastly  augmented  by 
the  carbonic  acid  which  r  gathers  from  the  atmosphere,  and 
this  is  the  chief  cause  of  tl  excavations  wrought  by  it  in  lime- 
stones. Pure  cold  water  I  -  comparatively  small  dissolving 
and  almost  no  eroding  power.  It  has  also  been  advocated  that 
various  acids  which  result  from  the  decay  of  vegetable  matter 
aid  in  such  results.'  This  may  be  true,  but  in  general  carbonic 
acid  is  the  chief  agent.  Iron  in  minerals  falls  an  easy  prey, 
as  does  calcium,  and  both  are  dissolved  out  in  large  amount. 
(See  Example  1.)  When  charged  with  alkaline  carbonates, 
water  has  the  power  to  attack  other  less  soluble  minerals,  such 
as  (juartz  and  silicates,  and  by  such  action  the  walls  of  a  cavity 
in  the  crystalline  rtxjks  may  be  much  affected. 


'  The  most  imiwrtant  works  bearing  on  tliis  entire  question  of  under- 
^ihiiikI  waters  are  those  of  Daiibree,  viz. : 

I'-tmles  Syntlietiqnes  de-  (i!eoh)gie  Experinientale,  "  1871). 

"Lea  Eaux  Souterraines  aux  Epoques  anciennes,"  1887. 

"l.es  Eaux  Souterraines  a  lEptHjue  aetiielle,"  1HH7,  3  vols. 

Suf^gestive  reading  will  also  be  found  in  C.  R.   Van  Hise,  "  Metamorph- 
ism  of  Rocks  and  Rock  flowage.  Bull.  Geol.  Soc.  Amer.,  IX.  209. 

''  A.  A.  Julien,  Amur.  Asso.  Adv.  Scl,  1879,  p.  311. 


28 


K/JMPS  ORK  DEPOSITS. 


1.02. 1 S.  As  has  been  set  forth  in  n  jnevious  paragraph,  waters 
percolating  to  great  deptlis  in  the  earth,  or  circulating  in  re- 
gions of  igneous  disturbances,  become  highly  heated,  and  this 
too  at  great  j)ressure.  Under  such  circumstances  the  solvent 
action  is  very  strongly  increased,  and  all  the  elemc^nts  present 
in  the  rock-making  minerals  are  taken  into  solution.  Alka- 
line carbonates  are  formed  in  (pianti+^v:  silica  is  easily  dis- 
solved ;  alkaline  sulphides  result  in  less  amount:  and  even  the 
heaviest  and  least  tractable  metals  enter  into  solution,  either 
in  the  heated  waters  themselves,  or  in  the  alkaline  licjuors 
formed  bj'  them.  The  action  on  the  walls  of  cavities  and 
courses  of  drainage  is  thus  profound,  and  accounts  for  the  fre- 
quent decomposed  character  of  the  walls  and  the  general  lack 
of  shar])ness  in  their  definition.  The  vast  amount  of  siliceous 
material  deposited  by  hot  springs  and  geysers  is  additional  evi- 
dence of  its  importance.  When  the  uprising  sohitions  reach 
the  regions  of  diminished  temperature  and  pressure  they  con- 
tribute their  burden  of  dissolved  minerals  to  veins  and  surface 
accumulations. 

lAVl.  11».  The  composition  of  mineral  springs  is  of  the  great- 
est interest  in  this  connection, and  is  a  subject  tliat  has  received 
much  attention  in  recent  years.*  The  vast  majority  of  those 
recorded  contain  chiefly  silica  and  salts  of  alkalies  and  alkaline 
earths,  of  which  a  few  represent  the  gangue  minerals.  Here 
and  there,  however,  examples  with  metallic  contents  have  been 
detected,  and  in  several  instances  springs  have  been  met  in 
deep  mines  and  the  waters  have  been  analyzed.  Often  the  ore 
deposition,  as  indicated  by  these,  seems  to  have  ceased,  but 
again  eitlier  in  the  waters  themselves  or  in  crusts  formed  by 
them,  metallic  minerals  have  been  detected.  In  the  table  be- 
low the  first  seven  relate  to  American  cases,  the  last  three  to 


»  R.  N.  Braokett,  " Mineral  Waters  of  Arkansas,'"  Geological  Survey  of 
Arkansas,  ISSIt,  I. 

Cioocli  and  Wliitfield,  "Analyses  of  Waters  of  the  Yellowstone  National 
Park,"  Bulletin  4r,  U.  S.  Geol.  Survey. 

A.  C.  Peale,  "Lists  and  Analyses  of  the  Mineral  Springs  of  the  United 
States,  Bulletin  32.  Idem. 

F.  Posppnj',  "Genesis  of  Ore  Deposits,"  pp.  20-48. 

J.  Rotli,  "  Allgenieine  und  Chemisi-lie  (jleologie,"  I.  Chap,  x.,  407. 

P.  Sohweitzer,   "Tne  Mineral  Springs  of  Missouri,"  Mo.  Geol.  Survey, 
in.  1893. 


ON  THE  FORMATION  OF  CAVniES  IN  ROCKS. 


29 


European.     All  the  amounts  are  expressed  in  parts  per  mil- 
lion, i.  e.,  grams  per  1, ()()()  liters. 

1.02.'^0,  In  analyses  I.  and  II.  metallic  salts  were  not  them- 
selves detected,  but  ammonimn  carbonate  was,  and  on  its 
presence,  as  well  as  the  results  of  experiment,  Becker  bases  his 
explanation  of  the  introduction  of  the  cinnabar.  Cinnabar  is 
found  to  be  sohible  in  ammoniacal  li(iuors  under  pressure  and 
heat,  but  to  preci})itate  again  as  the  pressure  and  temperature 
fall.  The  water  from  Steamboat  Springs  did  yield  traces  of 
quicksilver,  but  the  crusts  which  had  been  precipitated  at  the 
surface  of  the  ground  in  past  time  afforded  in  this  order:  sul- 
phides of  arsenic  and  antimonj',  ferric  hydrate,  lead  sulphide, 
copper  sulpliide,  mercuric  sulphide,  gold  and  silver,  and  traces 
of  zinc,  manganese,  nickel  and  cobalt.'  The  waters  from  the 
Geyser  mine  were  of  exceptional  interest.  When  compared 
with  each  other  it  is  noticeable  that  the  vadose  waters  (IV.) 
have  much  less  metallic  matter  than  the  deep-Avater  (V.),  and 
that  in  the  latter  the  metals  appear  in  much  the  same  relative 
abundance  as  in  the  ore  (VI.  and  VII.).  In  the  "Genesis  of  Ore 
Deposits,"  from  which  analyses  VIII.,  IX.  and  X.  have  been 
taken,  Posepny  has  collected  man}'  more,  and  cites  some  in- 
stances abroad  in  which  the  metals  have  also  been  notetl.  An- 
timony, arsenic,  bisnuith,  iron,  manganese,  coj)per,  tin,  cobalt, 
nickel,  lead,  zinc  and  uranium  are  to  be  numbered  among 
them.  So  far  as  the  metals  are  concerned  all  the  analyses  in- 
dicate extremely  dilute  solutions,  and  the  waters  must  have 
n'(|ui]od  a  very  long  ])eriod  of  time  to  yield  the  ore  liodies. 
The  dissolved  content  of  alkaline  salts  must  have  flowed  away 
on  the  surface  and  have  disappeared. 

I.  Water  from  the  Hermann  shaft  at  Suli^hur  Bank,  Califor- 
nia, from  a  quicksilver  mine.  Monograph  Xlll.,  U.  S.  Geol. 
Hin-ri'ii,  p.  251).    W.  H.  Melville,  Analyst. 

II.  Parrott  shaft,  same  locality.     Jdcni. 

III.  Steand)oat  Springs,  Nev.     Idem.  ]>.  'Ai'.K 

IV.  Calculated  composition  of  the  vadose  water  at  the  500- 
it.  level  of  the  Geyser  silver  mine.  Silver  Cliff,  Colo.,  in  rhj'o- 
lit(*  tuff.  The  analysis  is  made  up  from  analyses  of  the  water 
and  of  the  sediment  that  settled  from  it,  chiefly  by  preciinta- 


si. 


^Monoqrnph  XIII.,  U.  S.  Geol  Siinrj/,  343. 


30 


KEMPS  ORE  DEPOSITS. 


I. 

11. 

III. 

IV. 

V. 

SiOg             

37.15 

41.85 

25.90 

84.48 

AlgOj               

0.25 

1.06 

ALO«    PoOft 

0.80 

L.'^iO 

1.70 

93.50 

FeC'og 

0.98 

0.29 

7.25 

MnC'o-j   » 

1 .19 

35.  yo 

23. -10 

50.55 

15.77 

300.03 

C;i«I'n(»^     

1.37 

Trace. 

Cat",  

Trace. 

SrC(  )3 

3.29 

MkCUs 

K-SO. 

18.90 

5.55 

0.99 

42.85 

4.20 

10.00 

621.84 
19.18 

KW 

KHr  KI 

47.05 

74.70 

197.35 

301.. ■J4 
Trace 

Xil  j(.'(  jg 

1.9-l(i.75 

322.00 
OKI).  05 

l,o;i9.7-5 

43.14 

111.47 

1.4U.75 

38.70 
60.50 

1,489.07 
223.53 

NiioSOj 

NnCl      

1,102.70 

N1VNO3    



2.19 

Niio}i.("), 

l,8i8.40 

2,404.35 

313. (1« 

39(1.!  10 

2».)0.23 

3.  ,58 

8.(10 

1.00 

50.50 

Trace. 

NflnSi.On 

NalKJOs 

NallS  

NAjAsSj 

NiijShSa 

IjnSO. 

\M'\       

17.30 

(NlDoCO, 

(>.fi4 

4..')5 

202.41 

5.00 

2.H2 

0.74 

1,751.31 

7.6 

HoS 

CO3 

37.20 

1,418.61 

HkS,  nXajS 

Trace. 

Pl)C(>3 

Trace. 
Trace. 
(1.40 

1.74 

CUC03 

0.(14 

Zn(  'Oj 

0.06 

Gold 

Silver 

TiPad 

Zinc 

Clipper 

Iron 

Miiiif^ancse 

Lime 

Hnlplnu" 

Silica 

Total.... 


VI. 

Trace, 

VI. 

Trace. 

1.05 

1.2.- 

2:i.8o 

17.00 

14. (H) 

11.10 

1.50 

2.30 

2.. -id 

2.00 

1.21) 

0.80 

1.70 
12.00 

9.,'-)() 

,33.00 

40.90 

91.75 

91.47 

AlU.  Carlionates  .... 
i'lartliv    l"i(rl)on,ites 

Alk.  Snlpliatcs 

Is.ii'tliy  Snli)liiites... 

(!lili)ri(les 

Silica 

( )tliers 


VIII. 


.3,52.00 
.55.(10 
12.no 


0.(HI 
51.00 


IX. 


1.150.00 

5in.n(t 

82  00 


02.00 


X. 


2.297. («) 

729  (10 

37.(:i) 

n.iiO 

.58.(K) 

72.00 

0.00 


tion  in  tliecarbo}-.  XVII.  Ann.  Rep.  Dir.  U.  S.  Geol.  Siirv., 
Part  II.,  p.  4(i;i.      W.  F.  Hillcbrand,  Analyst. 

V.  Calculated  composition  of  deep  M^ate.'s,  2,000-ft.  level, 
same  place  an.i  conditions.     Jiicin. 

VI.,  VII,  Analyses  of  two  carload  lots  of  ore  from  same 
mine,  made  at  Arkansas  Valley  smelter,  Leadville.  Ideiii, 
p.  4.57.    The  gangiie  was  chie  iy  barito,  calcite  and  chalcedony. 

VIII.  Water  from  the  Einigkeit's  shaft,  Joachimsthal,  Bo- 
hemia, presumably  at  a  deptliof /):j.'{  meters  (1,774  ft.),  as  stated 
on  p.  27  of  citation.  Analysis  en  p.  1)8,  "Oenesis  of  Ore  Deposits." 


'ON  THE  FOliMA  TION  OF  CA  VITIE8  IN  ROCKS. 


31 


84.43 
1.06 


7.y5 

Mil 
3liC.03 


Ti'nce. 
Trace. 
3.  SI) 
621. H4 
I'J.IB 
301.  :J4 
Trace. 
l,4W>.ti7 
823.53 


17.30 

"Mis.oi 


1.74 
0.04 
0.06 


1 

X. 

2.207. (H) 

720  00 

37.1  iO 

O.fiO 

.58.(K) 

TO.OO 

0.00 

Analyst,  J.    Seifert.      The  table    of  equivalent  temperatures 
on  p.  3?  of  original  is  incorrect. 

IX.  Gottesgeschick  mine,  Schwarzenberg,  Saxony.    Idem. 
Analyst,  R.  Richter. 

X.  "Sprudel"  spring  in  a  colliery  at  Brux,  Bohemia.  Idem. 
Analyst,  J.  Gintl. 

l.()-^.20.  Magnesia  is  one  of  the  alkaline  earths  readily 
taken  into  solution  by  carbonated  waters,  and  when  sucli  wa- 
ters again  meet  limestone  the  effect  is  often  very  great,  and 
constitutes  one  of  tlie  most  important  melbods  of  the  formation 
of  cavities.  Solutions  of  magnesium  carbonate,  on  meeting 
calcium  carbonate,  effect  a  partial  exchange  of  the  fortner  for 
the  l.'itter.  This  leaves  the  rock  a  double  carbonate  of  calcium 
and  magnesium,  which  is  the  composition  of  the  mineral  and 
rock  dolomite.  The  process  is  therefore  called  dolomitization. 
(See  Example  25.)  It  may  bring  about  a  general  shrinkage  of 
eleven  or  twelve  per  cent.  In  any  extended  thickness  of  strata 
this  would  cause  vast  shattering  and  porosity.  As  an  illus- 
tration of  its  results,  the  following  analysis  of  normal,  un- 
cliangod  Trenton  limestone  of  Ohio,  and  of  well  drillings  from 
the  porous,  gas-bearing,  dolomitized  portions  of  the  same,  are 
given.  They  are  taken  from  a  paper  by  Edward  Orton. 
{Ainer.  Manuf.  andiron  World,  Pittsburg,  Dec.  2,  1887.) 

CaCOs.  MgCO.,.  Fe,0,„Al20,.  SiO^. 
Unchanged  Trenton  limestone.  .70.30        0.93         7.00         12.00 

"  ..82.3(5  1.07  0.58  12.34 
Dolomitized       "  "         ..53.50      43.50         1.25  1.70 

'*  ..51.78      30.80 

l.oi.Jl.  Recent  studies  in  ore  deposits  by  Posepny,  Curtis 
and  Emmons  iu(1icHte  also  that  solutions  of  metallic  ores  may 
affect  an  interchange  of  their  contents  with  the  carbonate  of 
calcium  or  magnesium  in  limestones  and  dolomities,  leaving 
an  ore  body  in  place  of  the  rocks.  This  clumge  is  effected 
molecule  by  molecule,  and  is  spoken  of  as  a  metasomatic  inter- 
change or  replacement.  (See  P^xainple  30.)  By  "metasoma- 
tic" is  meant  an  interchange  of  substance  without,  as  in  pseu- 
d()iiiorj)hs,  an  imitation  of  form.  Alteration  of  the  metallic 
ores  may  follow  and  occasion  cavities  from  shrinkage.  (See 
Example  30,  and  Curtis,  on  Eureka,  Nev.,  Monoijraph  VIII, 
r.  S.  Ueol.  Surrey,  Chap.  VIII.) 


CHAPTER  III. 


THE  MINERALS    IMPORTANT    AS    ORES;    THE     GANGUE  MINER- 
ALS,   AND   THE   SOURCES   WHENCE   BOTH   ARE   DERIVED. 

1.03.01.  The  minonils  which  form  the  sources  of  the  metals 
are  almost  without  exception  included  in  the  following  com- 
pounds: the  sulphides  and  tellurides,  the  arsenides  and  antimo- 
nides,  the  oxides  and  oxidized  compounds  such  as  hydrous 
oxides,  carbonates,  sulphates,  phosphates,  aud  silicates,  and 
one  or  two  compounds  of  chlorine,  A  few  metals  occur  in 
the  native  state.  All  the  other  mineral  compounds  such  as  a 
chromateor  two,  a  bromide  or  iodide,  etc.,  are  rarities.  It  may 
be  said  that  nine-tenths  of  the  productive  ores  are  sulphides, 
oxides,  hydroxides,  carbonates,  and  native  metals.  The  ores 
of  each  metal  are  subsequently  outlined  before  its  particular 
deposits  are  described. 

1.01}. 0*^.  The  most  common  gangue  mineral  is  quartz,  while 
in  less  amount  are  found  calcite,  siderite,  barite,  fluorite,  and 
in  places  feldspar,  pyroxene,  hornblende,  rhodonite,  etc.  The 
silicates  are  chiefly  present  where  the  gangue  is  a  rock  and  the 
ore  is  disseminated  through  it.  All  the  common  rocks  serve  in 
this  capacity  in  one  place  or  another, 

1.03.0.'),  Source  of  the  Mcfdls. — The  metallic  contents  of 
the  minerals  which  constitute  ores  must  logically  be  referred 
to  a  source,  either  in  tlie  igneous  rocks,  or  in  the  ocean.  If 
the  nebular  hypothesis  expresses  the  truth — and  it  is  the  best 
formulation  that  we  have — all  rocks,  ignetuis.  sedimentary, 
and  metanior})hic,  must  be  traced  back  to  the  original  nebula, 
This,  in  cooling,  afforded  a  fused  magma,  which  chilled  and 
assumed  a  structure  analogous  to  the  igneous  rocks  with  which 
we  are  familiar.  Igneous  rocks  must  thus  necessarily  be  con- 
sidered to  have  furnished  l\y  their  erosion  and  degradation  tin* 
materials  of  the  sedimentary  rocks;  while  igvicous  and  sedi- 


THE  MINERALS  IMPORTANT  AS  ORES,  ETC. 


33 


inentury  alike  have  afforded  the  substances  whose  alterations 
liavo  produced  the  metamorphic  rocks.  It  may  also  be  true 
tli;it  eruptive  rocks,  especially  when  basic,  have  been  formed, 
by  the  oxidation  and  combination  with  silica,  of  inner  metallic 
portions  of  the  earth,  for  this  is  one  of  our  most  reasonable 
explanations  of  volcanic  phenomena,  suggested  alike  by  the 
conijiosition  of  basalts,  by  the  high  average  specific  gravity  of 
the  glol)e,  and  by  analogy  with  meteorites. 

l.do.oJ:.  As  opposed  to  this  conception,  there  are  those  who 
Avould  derive  the  metallic  elements  of  ores  from  the  ocean,  in 
which  they  have  been  dissolved  from  its  earliest  condensation. 
Thus  it  is  said  that  substantially  all  the  metals  are  in  solution 
ill  sea  water.  From  the  sea  they  are  separated  by  organic 
creatures,  it  maj'  be,  through  sulphurous  precipitation,  attend- 
ant on  the  decaj^  of  dead  bodies.  The  accumulations  of  the 
remains  of  organisms  britig  the  metals  into  the  sedimen- 
tary strata.  Oice  thus  entombed,  circulation  may  concentrate 
them  in  cavities.  When  present  in  igneous  rocks,  the  latter 
are  regarded  as  derived  from  fused  sediments.  If  the  metallic 
contents  of  sedimentary  rocks  do  not  come  from  the  ocean  in 
this  way,  the  igneous  rocks  as  outlined  above  are  the  only  pos- 
.sible  source.  No  special  mention  is  here  made  of  the  meta- 
morphic rocks,  because  in  their  original  state  they  are  rcifera- 
l)le  to  one  or  the  other  of  the  two  remaining  classes.  But  it  is 
lint  justifiable  in  the  absence  of  special  proof  to  consider  them 
altered  sediments,  any  more  than  altered  igneous  rocks,  and  it 
is  doubtless  true  that  the  too  generally  and  easily  admitted 
wdiinentary  origin  for  our  gneisses  and  schists  has  materiallj^ 
liiiulered  the  advance  of  our  knowledge  of  them  in  the  last 
forty  years. 

I.0;).O5.     Microscopic  study  of  the  igneous  rocks  has  shown 

Itliat,  with  few  exceptions,  the  rock-making  minerals  separate 

finm  H  fused  magma  on  cooling  and  crystallizing,  in  a  quite 

I  definite  order.  ^    Thus  the  first  to  form  are  certain  oxides,  mag- 

nrtite,  specular  hematite,  ilmenite,  rarely  chromite  and    pico- 

[tite.  a  few  silicates,  unimportant   in   this  connection  (zircon. 

tifaiiite),  and  the  sulphides  pyrite  and  pyrrhotite.     Next  after 

tliose  metallic  oxides,  etc.,  the  heavy,  dark-colored,  basic  liili- 


'  If.  Rosenbusch,  "Ueber  das  Wesen  der  koernigeii  vuid  ixn'plij'risrlien 
Stnictur  hei  Massengesteiiie."  Neues  Jahrhuch,  18S2,  ii.,  1, 


34 


KEMP'S  ORE  DEPOSITS. 


cates,  olivine,  biotite,  augite,  and  hornblende  are  formed.  All 
these  minerals  are  charactori/ed  by  high  i)ercentages  of  iron, 
magnesium,  calcium,  and  aluminum.  They  are  very  gener- 
ally provided  with  inclusions  of  the  first  set.  Following  tlie 
bisilicates  in  the  order  of  crystallization,  come  the  feldspars, 
and  after  these  the  residual  silica,  which  remains  uncombined, 
separates  as  quartz. 

1.0:5.01).  If  we  regard  the  igneous  rocks  as  the  source,  the 
metallic  elements  are  thus  to  bo  ascribed  to  the  first  and  sec- 
ond series  of  crystallizations,  while  the  elements  of  the  gangue 
minerals  are  derived  from  the  last  three.  It  is  a  doubtfid  point 
whether  the  less  common  metals,  such  as  cojiper,  silver  and 
nickel,  enter  into  the  composition  of  the  dark  silicates  as  bases, 
replacing  the  iron,  alumina,  lime,  etc.,  or  whether  they  are 
jiresent  in  them  })urely  as  inclusions  of  the  first  series.  F. 
Saudberger'  argues  in  supi)ort  of  the  first  view,  but  his  critics, 
notably  A.  W.  Stelzner,  cast  doubt  upon  his  conclusions  ou  tlio 
ground  that  his  chemical  methods  were  indecisive.  The  case 
is  briefly  this:  Sandberger,  as  an  advocate  of  views  which  will 
be  svil)se(iuently  outlined,  separated  the  dnrk  silicates  of  a  great 
many  rocks.  By  o))erating  on  (piantities  of  thirty  grams  he 
proved  the  presence  in  them  of  lead,  copper,  tin,  antimony, 
arsenic,  nickel,  cobalt,  bismuth,  and  silver,  and  considered 
these  metals  to  act  as  bases.  The  weak  point  of  the  demonstra- 
tion consists  in  dissolving  out  from  the  powdered  silicate  any 
possible  inclusions.  There  seems  to  be  no  available  solvent 
which  will  take  the  inclusions  and  be  without  effect  on  tlie 
silicates.  This  is  the  point  attacked  by  the  critics,  and  a])pa- 
rently  with  reason.  It  is,  however,  important  to  have  shown 
the  presence  of  these  metals,  even  though  their  exact  relations 
be  thus  doubtful.  Quite  recently  in  a  series  of  "Notes  on  Cliil- 
ean  Ore  Deposits."  Dr.  Moricke"  mentions  native  gold  in 
pearlstone  (obsidian)  from  Guanaco,  in  skeleton  crystals  in  the 

'  The  prin('ii)al  ]iaiH>r  of  Professor  Sandberger  is  liis  "Untersuchiinf;i'!i 
fiber  Erz}j;ange, "  ISS'2,  abstracted  in  tlie  EiKjincerhig  and  Miuiin] 
Journal,  March  15,  22,  and  29,  1884;  but  a  long  series  of  others  might  lie 
cited  ir.  which  the  investigations,  notably  at  Pribram.  Bohemia,  are  in- 
terpreted as  indicated  above  A.  W.  Stelzner,  B.  a  ml  If.  Zi'it..  xxxix.,  Xo, 
3,  Zcifsch.  (I.  (I.  g.  Gesell. ,  xxxi.  644.  "Die  Lateralsecretions-Tlieorie,  etc." 
Reprint  Freiberg,  1H8!K 

■•'  Tscnermaks  Min.  and  Pctrog.  Mitth.,  Xll..  j;.  li)."). 


TUh:  MINERALS  IMPORTANT  AS  ORES,   ETC. 


35 


glass,  as  inclusions  in  perfectly  fresh  plagioclase  and  sanidine 
crystals,  and  in  spherulites.     G.  P.  Merrill  has  recorded  gold 
!is  an  original  mineral  in  biotite-granite  from  Sonora,  Mexico.' 
A.  Simundi  reported  years  ago  the  existence  of  gold  in  the  gran- 
ites of  Owyhee  Co.,  Idaho,  far  from  any   vein,  to  an  amount 
etiual  to  ih  cents  per  ton.^     The  existence  of  silver  in  (juartz- 
porphyry  has  been  demonstrated  in  this  country  by  J.  S.  Curtis, 
at  Eureka,  Nev. ;'-  both  the  precious  metals  have  been  shown  by 
G.  F.  Becker  to  be  in  the  diabase  near  the  Comstock  Lode ;''  and, 
by  the  same  investigator,  antimony,   arsenic,  lead  and  copper, 
wore    proved  to  bo    contained   in  the    granite    near    Steam- 
boat   Springs,    Nov.*     S.    F.    Emmons   has   also   shown   that 
the  porphyries  at  Leadville  contain  appreciable,  though  small, 
amounts  of  silver."     Of  forty-two  specimens  tested,  thirty -two 
afforded  it ;  of  seventeen  tested  for  lead,  fourteen  j'ielded  results. 
Enunons  has  also  recorded  determinations  of  silver  by  L.  G. 
Eakins  in  the  eruptive  rocks  of  Custer  Co.,  Colo.,  in  connection 
with  investigations  upon  the  interesting  ore-bodies  of  the  dis- 
trict.    Nine  rocks  were  assayed,  embracing  trachytes,  an  ande- 
site-breccin,  a  different   andesite,  rhyolite,  red    grantite.  black 
granite,  the  se})arated  bisiliates  of  the  last-named,  and  diorite. 
Five  out  of  the  nine  contained  appreciable  amounts,  viz.,  one 
tracihyte,  the    rhyolite.  the    diorite,  and    both    granites.     The 
amounts  vary  from  0.005  to  0.402  of  an  ounce  per  ton.     The 
separated  hisilicates  yielded  0.045  per  cent,  lead  and  0.04  of  an 
(nmce  of  silver."     Undoubtedly  the  midtiplication  of  tests  will 
sliow  similar   metallic   contents  in  other  regions.     Thus  the 
aiigite  of  the  eastern  Triassic  diabase  will  probably  yield  cop- 
per, for  this  metal  is  abundant  in  connection  with  the  outflows. 
1.0:5.07.     Among  the  igneous  rocks  certain  metals  seem  to 
be   cliaracteristically   associated   with  some  varieties,    others 
again  with  a  different  series,  while  to  many  no  generalizations 
api)ly.     The  basic  rocks  are  the  richest  in  iron,  but  the  metal 
i-^  not  lacking  in  the  most  acidic.     Copper  in  association  with 

'  (t.  p.  Merrill,  Gold  in  Granite,  Amer.    Jour.   Scl,  April  1896,  309,  Si- 
tiuinili's  results  are  given  by  G.  F.  Becker.— roi^/i  Census,  XIII.  52. 
''  Moiiof/mph  VTl.  U.S.  Geol.  Siirvri/.  p.  MO. 
'  Moiio(jrapli  III.,  U.  S.  Geol.  Siirven. 
'  Moiuigntph  XIII.,  U.  S.  Oeol.  Survey,  p.  850. 
'  ^fo)io()r(i])h  XIL,  U.  S.  Geol.  Surve;/,  p.  5fi9. 
'  A'T7/.  Annual  Rep.  Director  U.  S.  Geol.  Sinreij,  Part  II.,  471. 


'M 


Jih\VP\S  OJiE  UK  POSITS. 


niokel  and  some  cobalt  is  found  in  widely  separated  parts  of 
the  world  in  basic  gabbros,  but  other  cases  are  ecjually  pro- 
nounced in  which  it  seems  connected  with  igneous  rocks  of 
medium  acidity,  or  with  sediments  having  no  visible  conucc" 
tion  with  igneous  rocks  at  all.  The  greatest  copper  district  now 
productive, Butte, Mont.,  has  only  granites  and  rlu'olites  ((luart/- 
porphyries)  exposed  for  miles  around.  Lead  and  zinc  are  more 
commonly  associated  with  limestones  than  with  any  other  one 
rock,  but  the  precipitating  action  of  this  rock,  rather  than  any 
original  content  of  the  metals  in  it,  is  probably  res])onsible  for 
the  association.  In  other  respects  no  generalizations  are  possible 
Gold  and  silver  are  cosmopolitan  in  their  relations.  The 
former  has  been  foinid  in  the  native  state  in  igneous  granite 
and  perlite,  and  with  jij'rrhotite  in  basic  gabbros,  aside  from 
its  occurrence  in  veins.  Silver  in  one  locality  and  another  is 
a  companion  of  almost  all  tj'pes  of  rock;  chromium  and  jjlati- 
num  are  certainly  at  home  in  the  basic  peridotites  and  their 
serpentinous  alteration  products,  and  tin  is  seldom  seen  except 
in  connection  with  granite.  The  other  lesser  metals  that  are 
of  serious,  practical  importance  admit  of  no  general  statements 
that  are  not  largely  speculative. '  The  rarer  elements  do,  however 
present  some  striking  associations.  The  "rare  earths"  seldom 
if  ever  occur  in  notable  amount  except  in  pegmatites  and  gran- 
itic rocks.  Vanadium  finds  its  peculiar  home  in  titaniferous  mag- 
netite, but  it  is  of  remarkably  wide  distribution  in  basic  rocks 
in  general,  as  shown  by  over  sixty  analyses  by  Hillebrand  and 
Stokes."  The  amounts  are  small,  in  only  one  case  reaching  a 
tenth  of  one  per  cent.,  and  the  vanadium  favors  the  dark  sili- 
cates, especially  biotite.  It  has  also  been  detected  in  surpris- 
ing quantities  in  the  ashes  of  coals  in  Argentina  and  Peru.^ 

'  These  questions  liave  been  discussed  at  lengtli  by  L.  De  Launay, 
" Contribution  a  I'Etude  des  (Jites  Metalliferes,"  AnualcHcles  3Iincs,XU., 
18!)T,  110-238. 

J.  H.  L.  Vogt,  "  Ueber  die  relative  Verbreitung  der  Elemente,  besonders 
der  Sehwermetalle  uud  ueber  die  Concentration  des  lu'spriinglich  i'ciu 
vertheilten  Metallgehaltes  zu  Erzlagerstiitten.  Zeitsch.  fur  praktm'hc 
Geologie,  August,  1898,  to  January,  1899. 

^  W.  F.  Hillebrand.  "Distribution  and  Quantitative  Occurrence  of  Vana- 
dium and  Molybdenum  in  Rocks  of  the  United  States,"  xlmer.  Jour.  Sci. 
September,  1898,  209. 

^  W.  P.  Blake,  Engineering  and  Mining  Journal,  Aug.  11,  1894,  p.  I'H. 
Vanadium  has  been  detected  by  R.  S  McCaflfery,  E.  M.,  in  coals  used  at 
Casapalca,  Peiu. 


THE  MINKIIALS  TMPORTANT  AS  ORES,   ETC. 


37 


]\I()lyl)(lenum  is  much  rarer  atid  a])peHrH  to  be  limited  to  the 
aoiilic!  rocks.  Tlic  mineral  molybdenite  is  seldom  met  except 
in  pegmatites.  Tnugsten  has  practically  the  same  associa- 
tions as  tin. 

1.0:5.08.  That  the  metals  are  so  generally  combined  with 
sulpliur  in  ore  deposits  seems  to  be  due  to  the  extended  distri- 
Inition  of  this  element,  and  to  its  vigorous  precipitating  action 
on  nearly  all  the  metals  at  the  temjjeratures  and  ])ressures 
wliicli  })revail  near  the  earth's  siu'face.  Sulphur  is  widespread 
in  pyirhotite  and  pyrite,  original  minerals  in  many  igneous 
rocks,  and  ones  much  subject  to  alteration;  while  sulphuretted 
liydiogen  is  common  in  waters  from  sedimentary  rocks,  and  is 
a  very  general  result  of  organic  decomposition.  Natural  gas 
and  ])otroleum  from  limest(  ne  receptacles  almost  always  con- 
tain it.'  Many  sulphides,  too,  are  soluble  under  the  pressiu'es 
and  temperatures  prevailing  at  great  de})ths,  but  are  deposited 
spontaneously  at  the  pressures  and  temperatiu-es  prevailing  at 
or  near  the  surface. 

J. (i:i. ()'.».  Where  veins  occur  in  igneous  rocks  the  bases  for 
gangne  minerals  have  been  obtained  from  the  rock-making 
silicates.  Calcium  is  afforded  by  nearly  all  the  im])ortaiit 
ones;  silicon  is  everywhere  ju'esent ;  barium  has  been  proved  in 
many  feldspars,  in  small  amount ;  and  magnesia  is  present  in 
many  pjToxeiies  and  amphiboles.  ()f  tlie  sedimentary  rocks, 
limestone  of  course  affords  mdimited  calcium,  and  recently 
Sandberger  reports  tiiathehas  identified  microsco{)ic  crystals  of 
bai'ite  in  tlie  insolul)le  residues  of  one.'"  This  is  of  interest,  as 
barite  is  such  a  common  gangue  in  limestone. 

l.o:i.l(».  It  maybe  remarked  that  the  natural  formation  of 
both  ore  and  gangue  minerals  has  doubtless  in-oceeded  in  na- 
lure  with  great  slowness,  and  from  very  dilute  solutions.  Both 
( lapses  exhibit  a  tendency  to  concentrate  in  cavities,  even  from 
a  widely  dispersed  condition  tlnough  great  masses  oi  compara- 
tively barren  rock.  The  formation  may  have  proceeded  wdien 
the  walls  were  far  below  their  present  i)osit ion  with  regard  to 

'  See,  in  this  connection,  J.    F.Kemp,    "Tlie  Precipitation   of  Metallic 

Suipliidcsby  Xatnral  (iiis,"  Enr/iiircriiHi  and  M'niiiKj  .fi)iir>i(il,  Dec.  1:5,  IMJIO. 
-  Sit':iiiHj.sli(ricliti' <t.  Mutli.  j)li!in.  ('/((sscd  k.  btijirv,  Akad.  d.  Wish., 
l^'.U,  xxi.  2111.  See  also,  W.  F.  Hillebraml,  "Tiie  Widespread  Occurrence 
"t  l^arium  and  Strontium,  in  Silicate  Rocks." — Jour.  Ainer.  Che  in.  Sue, 
February,  1«94,  p.  81. 


38 


KKMP'i^  OIU'J  DKPOSITS. 


tlie  surface,  ho  that  to  those  inclined  a  wide  latitude  for  Hpecu- 
lation  on  ori^i"  ih  afforded.  It  is  juwHible  that  in  the  earlier 
history  of  the  globe  circulations  were  more  active  than  they 
are  now — a  line  of  argument  on  which  a  conservative  writor 
would  hesitate  to  enlarge. 

l.OJKll.  In  the  above  discussion  of  the  sources  of  the  ores 
and  gangue,  the  vein-tilling  has  been  considered  as  primarily 
derived  from  the  barren  wall  rock  or  from  deep-seated  st)urces, 
and  as  precipitated  in  its  present  position  in  the  first  concen- 
tration. Yet  in  instances  it  is  by  no  means  improbable  that 
vein-fillings  as  found  to-day  are  the  product  of  several  concen- 
trations, and  that  a  deposit  sufficientl}-  rich  to  work  may  he 
the  result  of  two,  or  more  nn'grations  since  the  first  dejiar- 
ture  from  an  originally  s])arsoly  disseminated  condition  in  the 
mother  rock.  L.  De  Launay  has  elaborated  this  view  in  tiie 
paper  cited  abcve.^  In  a  later  paragraph  of  this  book,  1.05.0(1, 
the  secondary  alterations  of  those  portions  of  veins  that  lie  iu 
the  region  of  the  vadose  circulation  is  taken  up,  but  M,  De 
Launay  carries  the  idea  much  further  in  suggesting  that  in 
many  veins  the  present  tilling  may  be  due  to  the  concentration 
of  ore  from  much  more  of  the  vein  than  now  appears  above 
the  rich  places.  It  is  certainly  true,  that,  if  a  vein  were 
formed  several  geological  periods  back, it  would  have  shared 
in  all  the  elevations  and  depressions  to  which  its  region  had 
been  subjected  and  consecjuently  to  considerable  changes  in  tlie 
relations  of  the  ground  water  and  the  vadose  circulations.  An 
explanation  would  also  be  afforded  of  the  richness  of  sonio 
veins  that  has  been  marked  within  limited  distances  of  the 
surface  and  that  has  decreased  in  depth.  W.  H.  Weed  has 
noted  cases  of  this  character  in  Montana  that  are  not  as  yet 
(181)1))  described  in  print. 

*  The  full  title  of  M.  De  Launay's  paper  is:  I.  Sur  1'  importance  des 
{fjtes  d'  inchisiou  et  de  se^rcf^iition  dans  uTie  classification  des  jjjites  nietiil- 
lifcres.  II.  Sur  le  role  des  pht-uonienes  d'alteratiou  su])i'rliciello  et  lie 
remise  en  mouvement  dans  la  constitution  de  ces  f^isenients.  This 
may  Ito  freely  translated.  I.  On  the  imi)ortanee  of  niajjj'uatic  inclusions 
and  sef,'re}j;ations  in  a  classiticatioii  of  ore  deposits.  II.  On  the  part 
played  by  phenomena  of  sui)erHcial  alteration  aud  of  the  renewal  of 
migration  in  the  constitution  of  these  deposits. 


CHAPTER  IV. 


ON*  THE   FILLING   OF   MINERAL  VEINS. 

1.04.01.     Bearing  in  mind  wliut  procedes,  the  preliminaries 
for  tiie  discussion  of  mineral  veins  are  set  in  order.     We  have 
traced  tiie  formation  of  cavities  by  the  slu'inkaf^e  of  rock  masses 
in  cnoliug  or  (h-ying,  by  the  movements  and  disturbances  of 
the  earth's  crust  (wliich  are  far  the  connnonost  and  niost  im- 
portant causes),  and  by  dolomitization.     The  enlargement  of 
sucii  cavities  hy  subterranean  circulations  followed,  and  the 
general  effect  of  waters,  cold  and  heated.     The  sources  of  the 
elenients  of  the  useful   minerals   were  pointcnl   out  so  far  as 
known.    All  these  general  and  indisputable  truths  assist  in  the 
drawing  of  right  conclusions.     It  should   be  emphasized,  as 
will  appear  later,  that  mineral  veins  or  cavity  fillings  do  not 
end)race  all  metalliferous  deposits.     On  the  contrary,  the  de- 
jjosits  which  either  form  beds  hy  themselves,  or  which  are  dis- 
seminated thrnngli  beds  of  barren  rock  and  are  of  the  same  age 
with  them,  do  not  enter  into  the  discussion.     They  are  charac- 
terized by  being  j'ounger  than  their  foot  walls,  and  older  than 
tilt!  hanging.     Their  geological  structure  is  far  simpler,  and, 
as  will  appear  in  the  discussion  of  particular  examples,  the 
woiking  out  of  their  origin  does  not  so  often  carrj'  the  investi- 
^'ator  into  the  realms  of  speculation  and  hypothesis.     And  yet 
it  is  not  to  be  inferred  from  the  ju'ominence  here  given  to  the 
discussion  of  veins  that  bedded  deposits  yield  to  them,  in  any 
degree,  in  importance.     Iron  ores,  for   instance,  are  often   in 
beds. 

1.04.02.  Methods  of  Filling— Methods  of  filling  were 
summed  up  a  very  long  time  ago  by  Von  Herder  and  Von 
Cotta,'  as  follows:  1.  Contemporaneous  formation.  2.   Lateral 

^  Erzlagemtatten.  2d  ed.,  1859.  Vol.,  I.,  p.  173.  A  later  talwlation  is 
given  hy  G.  F.  Becker  iu  Monugruph  XIII,   U.  S.  Geological  Survey,  pp. 

■Ill,  id 


40 


h'h'MP'S  (UIK  DKI'DSITS. 


soerction.  '.\.  T)osc(MiHi()n.  4.  AHceiiHion  by  (<i)  infiltnitioii. 
or  {h)  Huljliniatioii  with  wtoani,  or  (<•)  liy  siililiinatioii  as  ga.4,  or 
((/)  by  igneous  injection.  To  tliese  Hhould  be  added  the  niuro 
recent  theory  of  (5)  replaceinciit.  which,  liowever,  in  rather  a 
method  of  })reoipitation  than  (»f  derivation.  No  one  longer  be- 
li(u-eH  in  coiitiMiiporancons  formation,  and  descension  has  ;in 
extrciiu'ly  limited,  if.  indeed,  any  application.  AscenHion  Ity 
sublimation  as  gas  or  with  steam,  or  by  igneous  injection,  has 
very  few  good  api)lications.  The  discussion  is  [)ractically  re- 
duced to  lateral  secretion  and  to  ascension  by  infiltration. 

1.04.();5.  Jjdtci'iil  Sccrcfioit, — Hy  lateral  secretion  is  under- 
stood the  derivation  of  the  contents  of  a  vein  from  tho  ■wall 
rock.  The  wall  vvck  may  vary  in  character  along  the  strike 
and  in  depth.  Tlu'ce  interpretations  niay  bo  made,  two  of 
which  approach  a  common  middle  ground  with  ascension  hy 
infiltrativin.  It  may  first  be  sup])osed  that  the  vein  has  been 
filled  by  the  waters  near  the  surface  which  are  known  to  lio 
soaking  through  all  bodies  of  rock,  even  where  no  marked 
waterway  exists,  and  which  seep  from  the  walls  of  any  openiiij;' 
that  may  be  afforded.  Being  at  or  within  comparatively  short 
distances  of  the  surface,  the  waters  are  not  especially  iK^ated. 
As  they  emerge  to  the  oxidizing  and  evaporating  influence  ot 
the  air  in  the  cavity,  their  burden  of  minerals  is  dej)osited  as 
layers  on  the  walls.  The  second  intci'pretation  supposes  the 
walls  to  be  })laced  during  the  time  of  the  filling  at  consider.i- 
ble  depths  below  the  surface,  so  that  the  {)ercolating  waters  are 
brought  within  the  regions  of  elevated  temperature  and  pres- 
sure. Essentially  the  same  action  takes  place  as  in  the  first 
case.  The  third  interpretation  increases  the  extent  of  the  rock 
leached.  Thus,  if  a  mass  of  granite  incloses  a  vein  and  ex- 
tends to  vast  depths,  we  may  suppose  the  waters  to  come  from 
considerable  distances,  and  to  derive  their  dissolved  minerals 
from  a  great  amount  of  rock  of  the  same  kii"^  ills. 

Portions  of  this  may  even  be  in  the  regioTis  '  nera- 

ture,  while  the  place  of   prccipitatio-  u^^        face. 

These  last  two  interpretations  have  nu  in  co'  -on  \^  ith  tlie 
theory  of  ascension  by  infiltration,  and  un  this  '  unmon  middle 
ground  lateral-secretiouists  and  infiltratiou-abA  ^iisiouists  may 
be  in  harmony. 

1.04.04:.     Ascension  hy  Infiltration. — The  theorv  of  iufil- 


ON  THE  FILLINO  OF  MINKUAL   VEINS. 


41 


tratioti  liy  ascctision  in  solution  from  below  connidors  that  ore- 
liiiiriu}^  solutions  como  from  tlio  lu'atcd  zones  of  the  earth,  and 
that  they  rise  throiij^h  cavities,  and  at  diminished  temperatures 
and  pressures  deposit  their  burdens.  No  restriction  is  placed 
on  the  source  from  which  the  mineral  matter  has  been  derived. 
Indeed,  beyond  the  fact  that  it  is  "lielow,"  and  yet  within  the 
hmits  reached  by  waters,  all  of  which  have  descended  from  the 
surface,  and  that  the  metals  have  been  gathered  up  from  a  dis- 
seminated condition  in  rocks — igneous,  sedinu'utary  and  meta- 
morphic— no  more  definite  statement  is  possible.  This  theory 
is  of  necessity  largely  speculative,  because^  the  materials  for  its 
veritication  ari'  beyond  actual  investigation. 

1.04. (».■).  In  favor  of  lateral  secretion  the  following  argu- 
UK'nts  may  be  advanced.  I.  According  to  Sandberger,  actual 
experience  with  the  conduits,  either  natural  or  artificial,  of 
mineral  springs,  shows  that  a  dejxisit  seldom,  if  ever,  gathers 
in  a  moving  current.  It  is  only  when  solutions  come  to  rest 
oil  \\\o  surface  and  are  exposed  to  oxidation  and  evaporation 
tliat  precipitation  ensues.  Deixisits  in  veins  have  therefore 
formed  in  standing  waters,  whoso  slight  overflow  or  evapora- 
tion would  behest  compensated  by  the  etpially  slight  and  grad- 
ual inflow  from  the  walls.  If  in  hot  springs  there  were  a 
strong  and  continuous  flow  from  below,  and  discharge  from 
above,  tlie  nnneral  matter  Avould  reach  the  surl'aie.'  Hence  the 
(lei)()sit  would  bo  more  likel3'  to  gather  by  tiie  slow  infiltrations 
from  the  wall  rock,  which  would  stand  in  cavities  like  the 
water  of  a  well.  We  have,  however,  some  striking  instances 
of  deposits  in  artificial  conduits. 

Prof.  H.  S.  Munroe  has  called  the  writer's  attention  to  a  case 
met  by  him  in  18t)l.  The  fourteen-inch  column  ])ipe  of  a 
pumi)  at  the  Indian  Ridge  Collier}',  Shenandoah,  Pa.,  which 
was  raising  ferruginous  waters,  became  reduced  in  diameter  to 
five  inches  within  two  years  by  the  de])osit  of  limonite.  The 
same  amount  of  water  was  forced  through  the  five-inch  hole  as 
tliiniigli  the  fourteen-inch.  By  figuring  out  the  stroke  and 
cviiiuler  contents,  it  was  found  that  in  the  clear  pipe  the  water 
moved  I(J-i  feet  per  minute,  and  in  the  contracted  pipe  1,'^(j8 
feet.  And  yet  the  deposit  gathered.  The  conditions  necessi- 
tated the  continuous  action  of  the  jnnnp.  and  it  was  not  idle 
'  Sand  berger,  Untersudmnyeu  iiber  Erzgunye,  Heft  I. 


iliiij 


•      !, 


43 


KEMrs  OR]-:  DEPOSITS. 


over  two  hours  in  ench  two  niontlis  of  tlint  period.  The  boiler 
feed-pipes  of  steuniers  plyiug  ou  tlie  Great  Lakes  also  liecoine 
coated  with  salts  of  lime.  Years  ago  a  disastrous  boiler  ex- 
plosion occurred  from  the  virtual  stoppage  of  the  feed  by  this 
precipitation. 

l.()4.(»(;.  II.  If  a  vein  were  opened  uj),  in  nn'ning,  which 
ran  through  two  different  kinds  of  rock,  and  if  in  the  one  rock 
one  kind  of  ore  and  gangiie  minerals  were  found,  and  in  the 
other  a  different  set,  the  wall  rock  would  clearly  have  some 
intitience.  Thus  in  a  mine  at  Schapbach,  in  the  Black  Forest, 
investigated  by  Sandberger,  a  vein  ran  through  granite  and 
gneiss.  The  mica  of  tlie  granite  contained  arsenic,  cojiper.  co- 
balt, bisnuith  and  silver,  but  no  lead.  The  iirincipal  ore  in 
this  portion  was  tetrahedrite.  The  mica  of  the  gneiss  con- 
tained lead,  co{)per,  cobalt,  and  bisnuith,  and  the  vein  held 
galena,  chalcopyrite,  and  a  rare  mineral,  schapbachite,  contain- 
ing bisnuith  and  silver,  but  probablj'  a  mixture  of  several  sul- 
phides. No  two  ores  were  common  to  both  parts  of  the  vein. 
Another  well-established  foreign  illustration  is  at  Klausen,  in 
the  Austrian  'J'yrol.  Lead,  silver,  and  zinc  occurred  in  the 
veins  where  they  cut  diorite  and  slates,  but  copper  where  mica 
schist  and  felsite  formed  the  walls.  In  America  there  are  a 
mmiber  of  similar  cases.  At  the  famous  Silver  Islet  mine^  on 
Lake  Superior  the  vein  runs  through  imaltered  flags  and 
shales,  and  then  crosses  and  faults  a  large  diorite  dike.  Where 
the  diorite  forms  the  walls,  the  vein  carries  native  silver  and 
sulphides  of  lead,  nickel,  zinc,  etc.,  but  where  the  flags  torni 
the  walls  the  vein  contains  onl}'  barren  calcite.  Along  the 
edges  of  the  estuary  Triassic  sandstones  of  the  Atlantic  border 
where  they  adjoin  Archean  gneiss,  a  number  of  veins  are 
foxmd  which  yield  lead  minerals,  while  in  the  sandstones  ne  ir 
the  well-known  diabase  sheets  and  dikes  are  others  carrying 
copi)er  ores.    It  was  early  remarked  by  J.  D.  Whitney  that  the 

'  \V.  M.  Courtis,  "On  Silver  Islet,"  E)igineei in(j  (iml  Minintj  Journul. 
Dee.  31,  ISTS.     Trans.  Aiiwr.  lii.st.  Miii.  Eiu/.,  V.  4T4. 

E.  D.  bif,'all,  (hoi.  Siirirn  of  CiDKKhi.  1H8T-8H.  p.  27.  H. 

F.  A.  Lowe,  "The  Silver  Islet  Mine, "  ete.,    EiKjiiifi'viiuj   (tiiil    Miiiiwj 
Journal.  Dec.  1(>.  1SS',>,  p.  -.ViX. 

T.  ]\l;icFiU-lane.  "Silver  Islet,"  Trans.  Anwr.,  Inst.  Min.  Eng.,  VIII.  22(1 
Canaih'an  Xafnrali.><t.  IV.  ;iH. 

MoDoriuott,  Entjiiweriny  and  Mining  Journal,  January,  1HT7. 


ON  THE  FILLING  OF  MINERAL    VEINS. 


43 


loud  was  usually  associated  with  the  gneiss,  Ihe  copper  with 
Ihj  diabase. 

1.0-i.O".  From  instances  like  these  it  is -inferred  that  the 
ores  were  derived  each  from  its  own  walls,  and  by  just  such  a 
leaching  action  by  cold  surface  waters  as  is  outlined  above. 
As  oi)})osed  to  this,  it  has  usually  been  claimed  that  each  })ar- 
ticular  wall  exerted  a  peculiar  selective  and  precipitating  ac- 
tion on  the  metals  found  adjacent  to  it  and  none  on  the  others, 
so  that  if  a  solution  arose  carr^'ing  both  sets,  each  came  down 
in  its  particular  surroundings  while  the  others  escaped.  Dr. 
W.  P.  Jenney  has  called  the  writer's  attention  to  such  a  case. 
The  Head  Center  mine,  in  the  Tombstone  district.  Arizona,  is 
on  a  vein  which  pierces  slates,  and  in  (me  place  forty  feet  of 
limestone.  In  the  slates  it  carried  high-grade  silver  ores,  with 
no  lead,  but  in  the  limestone,  lead-silver  ores.  A  rock  like 
limestone  might  well  exercise  a  precipitating  action,  which, 
however,  we  cannot  attribute  to  rocks  com})osed  of  the  more 
inert  silicates.  Again,  it  has  been  said  that  the  solutions  com- 
ing from  below  have  varied  in  different  portions  of  the  vein  or 
at  different  periods.  An  earlier  oi)ening  Avould  thus  be  tilled 
with  one  ore,  a  later  o[)ening  with  another.  Tliis  is  hypothet- 
ical, but  has  been  advanced  for  Klausen  by  Posepny.'  A  fnr- 
thei'  general  objection  to  the  first  interpretation  of  lateral  se- 
cret ion  is  the  weak  dissolving  power  of  cold  surface  waters,  and 
tliis  is  a  very  serious  one. 

1.04.08.  As  opposed  to  the  second  interpretation,  it  may  be 
advanced  that  jirecipitation  in  a  cavitj'  at  a  great  depth  would 
he  retarded  by  the  heat  and  the  i»ressure,  to  just  that  extent  to 
which  solution  in  the  neighboring  walls  would  be  aided.  The 
temperature  and  ju'cssure  being  ]iractically  tht>  same,  the  t(>n- 
(leii(;y  to  remain  in  solution  would  be  great  until  the  minei-als 
hud  reached  the  upper  regions  and  filled  the  cavity  b}'  ascen- 
sion. Under  such  circumstances  ores  Avould  only  be  deposited 
1k>1()w,  by  some  such  action  as  replacement.  To  the  third 
iiit(  rpretation  no  theoretical  objections  can  be  made. 

1.04.01).  Iiijilfrdtion  hi/  AsccNsioii. — On  the  side  of  iuHltra- 
tioii  by  ascension,  if  two  veins  or  sets  of  veins  were  found  in 
the  same  wall  rock,  but  with  different  kinds  of  ores  and  miner- 
als, the  conclusion  would  be  irrefutable  that  the  res})ective  so- 
'  Archill  f.  Praktischc  Oeoloyir.  p.  483. 


yi 


44 


KEMP'H  ORE  DEPOSITS. 


liitions  which  formed  them  had  come  from  two  different  sources 
below.  Thus  at  Butte,  Mont.,  there  is  a  great  development  of 
a  dark,  basic  granite.  It  contains  two  series  of  veins,  of  which 
one  produces  copper  sulphides  in  a  siliceous  gangiie,  while 
around  this  series,  to  the  south,  west  and  north  the  veins  yield 
sulphides  of  silver,  lead,  zinc,  find  iron,  also  in  a  siliceous 
gangue,  but  abundantl}^  associated  with  manganese  minerals, 
especially  rhodojiite.  No  manganese  occurs  in  the  copper  belt, 
nor  is  any  coi)per  found  in  the  silver  belt.  Such  results  could 
originate  only  in  different,  deep-seated  sources.  Again,  at 
Steamboat  Springs,  Nov.,  and  Sulj)hur  Bank,  Cal.,  the  hot 
springs  are  still  in  action  and  are  bringing  tlieir  bvu'deiis 
of  gaugue  and  ore  to  the  surface.  The  foru)er  has  afforded 
a  long  series  of  metals,  the  latter  chieHy  cinnabar.  G.  F. 
Becker'  has  shown  that  the  cinnabar  probably  comes  up  in 
solution  with  alkaline  sulphides. 

1.04. 1 (».  Re})laciune)it. — The  conception  of  replacement  is 
one  tliat  has  been  applied  of  late  years  by  sduio  of  the  most  re- 
liable observers.  About  ]ST;5  it  ap})ears  to  have  been  iirst  ex- 
tensively developed  by  Franz  F()se|)ny,  an  Austrian  geologist, 
in  relation  to  certain  lead-silver  deposits  at  Raibl,  in  the  Prov- 
ince of  Kaernthen.  At  nearly  the  same  time  it  was  suggested  by 
Pumpelly.  then  State  (Jeologist  oi  ^Missouri,  to  Adolph 
Schmidt,  who  was  engaged  in  studying  tlie  iron  dc^posits  of 
Pilot  Knob  andiron  ^Mountain  (see  E.\ampl(>s  11  and  11«), 
and  bj'  Schmidt  it  was  considered  applicable  to  them."  Some 
ten  years  later  J.  S.  Curtis,  at  the  suggestion  of  S.  F.  Emmons, 
based  his  exjilanatiou  of  the  formation  of  the  Eureka,  Nov., 
lead-silver  deposits  on  the  same  idea,  and  according  to  Em- 
mons (ISSCi)  it  holds  good  for  Leadville.  K.  D.  Irving,  wlm 
credited  Pumpelly  with  bringing  it  to  his  attention.  })ublishe(l 
in  1880  an  ex])lanation  of  the  hematite  ores  of  the  Penokee- 
Gogebic  range  (Example  Dc),  in  which  the  idea  is  applied,  and 
Van  Hise  has  since  elaborated  it.  la  the  process  of  replace- 
ment no  great  cavitj'  is  supposed  to  exist  previously.  There 
is    little,    in   fact,    but    a    circulation    or    pei-colation  of  ore- 


'  G.  F.  Becki  'Natural  Solutions  of  Cinnabar,  (iold,  and  Associate! 
Sulpliitlcs,"  Ainrr.  Jour.  Sci.,  III.,  xxxiii.  VM\\  Kitjhtli  Aint.  Rep.  Director 
U.  S.  (iciil  Siirrc!/.  MowMfriijjIi  XIJI.,  U.  S.  Uvol.  Siirvnj,  p.  ;{4;{. 

''  "Iron  Oif's  and  Coal  Fields,"  Missonri  Uvol.  Siinrij,  1878. 


ON  THE  FILLING  OF  MINERAL    VEINS. 


45 


beai'iug  solutions  which  exchange  their  metallic  contents, 
molecule  by  molecule,  for  the  substance  of  the  rock  mass. 
Wo  would  not  ordinarily  expect  the  ore  body  to  be  as  sharply 
detined  against  the  walls  as  when  it  tills  a  fissure,  but  rather  to 
fade  into  barren  material.  Thus  rock  may  be  impregnated  but 
not  entirely  replaced,  and,  while  apparently  unchanged,  yet 
carry  valuable  amounts  of  ore.  Some  of  the  ores  of  As})en, 
Colo.  (Example  oOd),  are  at  times  onlj'  to  be  distinguished  by 
assay  from  the  barren  limestones.  Yet  decomposition  may 
bring  out  the  limits  of  each. 

1.04.11.  The  chemistry  of  the  replacement  process  is  none 
too  well  understood,  but  it  presents  fewer  difficulties  when  ap- 
plied to  a  soluble  rock,  like  limestone  or  dolomite,  than  when 
rocks  composed  of  silicates  and  quartz  have  given  waj'  to  ores. 
Acid  solutions  would  readily  yield  to  calcium  carbonate;  but 
if  the  metals  are  present  as  sulphides,  some  reducing  agent, 
such  as  organic  matter,  is  necessary  in  order  to  change  the  me- 
tallic sulphate  to  sulphide.'  Or  else,  if  the  metallic  sulphides 
come  up  in  solution  with  alkaline  sulphides,  some  third  agent 
is  needed  to  remove  the  calcium  carbonate,  pari  passu  just  be- 
fore the  metallic  sulphide  is  precipitated.  It  must  be  con- 
fessed that  for  enormous  bodies  of  ore,  like  those  of  Leadville, 
the  small  amount  of  organic  matter  present  seems  hardly  ecjual 
to  the  task  assigned  it,  and  the  delicate  balance  of  the  latter 
case — causing  deposition  to  tread  so  closelj'  on  the  heels  of  rock 
removal,  in  order  to  avoid  assuming  an  exteniled  cavitj^ — 
makes  it  appear  that  the  entire  chemistry  of  the  process  is  per- 
haps hardly  understood. 

1.04.1^.  When  silicate  rocks  are  replaced,  leaving  a  sili- 
ct'ous  gangue,  the  i)rocess  may  have  been  somewhat  as  sug- 
^'ested  by  K.  C.  Hills  for  the  mines  of  the  Summit  district,  Rio 
Grande  County.  Colorado.'^  Alkaline  solutions  remove  silica 
and  have  slight  action  on  silicates,  but  solutions  acid  with 
sulphuric  acid  attack  silicates,  such  as  feldspar  and  biotite, 
remove  the  alumina  or  change  it  to  kaolin,  and  cause  the 
separation  of  free  silica.      In   the  alteration  products  abun- 


'ConiimreS.  F.  Emmons.  "  On  the   Replacement  of   lieadville   Lime- 
stones ami  Dolomites  by  Sulpiiides,"  Monograph  XII.,  U.  S.  Geol.  Survey, 

'See  Proc.  Colo.  Sci.  Soe.,  Vol.  I.,  p.  30. 


n 


46 


KEMPS  OliPJ  DEPOSITS. 


daiit  opportunity  wonld  be  afforded  for  the  precipitation  of 
sulphides,  which  would  in  part  at  least  replace  the  rock. 
Along  a  crack  or  line  of  drainage  definite  walls  would  thus 
easily  fade  out.  Such  phenomena  are  afforded  bj'  innumerable 
ore  deposits'  and  often  come  under  the  notice  of  every  one 
familiar  with  mining.  Yet  we  cannot  but  hope  that  in  the 
future  our  knowledge  of  the  chemical  reactions  involved  will 
he  increased. 

It  may  again  be  stated  that  the  formation  of  ore  deposits  has 
proceeded  with  great  slowness,  and  that  the  solutions  bringing 
the  metals  have  been,  bej-ond  (question,  veiy  dilute.  The  ex- 
tremely small  atnounts  of  the  metals  which  have  been  detected 
in  relatively  large  amounts  of  igneous  rocks,  even  by  the  most 
refined  analytical  methods,  have  necessarily  made  the  progress 
of  solution  a  protracted  one.  Curtis  records  some  careful  observ- 
ations on  the  growth  of  aragonite  at  Eureka,  Nev.,  where  he 
found  that  in  three  weeks,  so  long  as  wet  bj'  a  drop  of  water, 
the  crystals  increased  in  one  case  as  a  maximum  five-eighths  of 
an  inch,  and  in  another  three-eighths.  But  this  was  where 
tlie  whole  inclosing  mass  of  rock  consisted  of  the  compound 
deposited. 


*  See  R.  W.  Raymond,    discussion    of  S.    F.    Emmons'    "Notes  on  the 
Geology  of  Butte,  Mont.,"   Trans.  Amer.  Inst.   Min.  Eng.,  XVI.,  p.  59, 

1887. 


CHAPTER  V. 


ON   CERTAIN   STRUCTURAL    FEATURES   OF   MINERAL   VEINS. 

1.05.01.  Banded  Stnicfi(re. — ^Mineml  veins  sometimes  ex- 
hibit a  banded  strucure,  by  Avhicb  is  imderstood  the  arrange- 
ment of  tbe  ore  and  gangue  in  parallel  layers  tbat  correspond 
oil  opposite  walls.  They  are  most  conspicuous  wbere  the  walls 
are  well  defined.  Tbe  solutions  wbicb  bave  brougbt  tbe  niin- 
erals  bave  varied  from  time  to  time,  and  tbe  precipitated  coat- 
inp:s  correspond  to  tbese  variations.  Tbey  alternate  from 
gangue  to  ore,  it  may  be,  several  times  repeated.  Tbe  ore 
may  be  in  small  scattered  masses  preserving  a  distinct  lineal 
arrtmgement  in  tbe  midst  of  tbe  barren  quartz,  calcite,  barite, 
Huorite,  siderite,  etc.,  or  itself  be  so  abundant  as  to  afford 
continuous  parallel  streaks.  Tbe  commonest  ores  so  observed 
are  pyrite,  cbalcopyrite,  galena,  blende,  and  tbe  various  sul- 
phides of  silver.  Tbe  veins  of  tbe  Reese  River  district,  in  Ne- 
vada, fiu'uisli  good  illustrations  of  alternating  ruby  silver  ores 
and  (juartz.  Those  of  Gilpin  County,  Colorado  (Example  17c0» 
atVord  alternations  of  pyrite,  cbalcopyrite,  and  gangue.  (See 
figures  in  Endlicb's  report.  ILn/dcii's  Snrri'H,  IHTo,  p.  •iHi).) 
Th(^  Bassick  mine,  in  Colorado,  has  ])ebblos  remarkably  coated. 
Figure  (1  shows  a  vein  at  Newman  Hill,  near  Rico,  Colo. 

Handed  veins,  however,  except  of  a  rude  character,  are  not 
common  in  this  countr}-.  The}'  have  received  much  more  at- 
tention ill  Germany,  where,  especially  near  Freiberg,  they  show 
leniarkable  jierfection.  The  famous  Drei  Prinzen  Spat  V^ein, 
Fig.  by  Von  Weissenbach  and  copied  in  many  liooks,  has 
ten  Corresponding  alternations  of  six  different  minerals  on 
each  wall.  Banded  structure,  whether  of  veins  or  vuggs  or 
stalactites,  etc.,  has  been  called  "crustification"  by  Posepny, 
who  considers  it  an  infallible  symptom  of  deposition  from 
solution. 


48 


KEMP'S  ORE  BEPOJSITS. 


l.Oo.O'^,  A  line  of  cavities,  or  viigg.s,  is  often  seen  at  the 
central  portion  of  a  vein,  into  which  crystals  of  tlie  last-formeil 
minerals  protrude,  forming  a  comb  (see  Fig.  0).  These  may  pro- 
ject into  each  other  and  interlock — especially  in  quartz — form- 
ing a  comb  in  comb.  The  same  may  occur  between  side  lay- 
ers. These  cavities  are  a  most  prolitic  source  of  finely  crystal- 
lized minerals.  If,  after  the  fissure — perhaps  at  the  time  small 
— has  become  once  filled,  subse<j[uent  movement!:  take  place,  it 
may  strip  the  vein  from  one  wall  and  cause  a  new  series  of 
minerals  to  i)e  deposited,  with  the  previously  formed  vein  on 
one  side  and  the  wall  rock  on  the  other.  This  oc(;asions  un- 
symmetrical  fillings.    But  it  may  also  happen  that,  with  other- 


Wesl 


East 


D 

K 

si-' 

^     0 

o 

<D 
T3 

C 

a 
..CO 

(No  «   <o 

-go-S 

N 
-•J 

(0 

3 

o 

CO 

^ 

».« 

FiO. 


6. — Banded  Vein  at  Newman  Hill,  near  liieo,   Colo.       After  J. 
Farrish,   Proc.,    Colo.    Sci.  Soc.,  April  4,  ISOJ:  Engineering 
and  Mining  Journal,  Angnnt  20,  18'J2. 


wise  symmetrical  fillings,  one  layer  may  be  lacking  on  one  side 
cr  the  other.  Where  portions  of  the  wall  rock  have  been  torn 
off  by  the  vein  matter  in  these  secondary  movements,  they  may 
be  buried  in  the  later  deposited  vein  filling,  and  form  great 
masses  of  barren  rock  called  "horses."  The  vein  then  forks 
aroimd  them.  If  the  ore  and  the  gangue  have  partly  replaced 
the  wall  in  deposition,  unchanged  masses  of  wall  maj'  also 
become  inclosed  and  afford  horses  of  a  different  origin.  An 
originally  forked  fissure  gives  an  analogous  result. 

It  is  a  curious  fact  that  veins  are  often  most  i)roductive  just 
at  the  split.    If  the  masses  are  small,  or  if  the  vein  fills  a  shat- 


()\  STRUCTUllAL  FEATURES  OF  MINERAL    VEINS.      49 


tei'iui  stri})  and  not  a  clean  fissure,  or  if  it  occupies  an  old  vol- 
canic conduit,  deposition  and  replacement  may  surround  un- 
clianj4ed  cores  of  wall  rock  with  concentric  layers  of  ores  and 
niiuorals.  Thus  the  Bassick,  at  Kosita,  Colo.,  referred  to  above, 
consists  of  rounded  cores  of  andosite,  inclosed  in  five  concentric 
layers  of  metallic  sulphides.  The  Bull  Doiningo.  in  the  same 
rc^'ion.  exhihits  shells  of  galena  and  (juartz  mantling  nodules 
of  gneiss.  Such  cores  strongly  resemble  roinided,  water-worn 
boulders,  a  similarity  which,  has  suggested  some  rather  iniprob- 
alile  hypotheses  of  deposition. 

l.()").();5.  CUtu  Selvage. — An  extremely  common  feature  is 
a  band  of  clay,  most  often  between  the  vein  matter  and  the 
wall.  This  is  called  a  selvage,  gouge,  Hucan.  claj'  seam,  or 
parting.  It  may  come  in  also  between  layers  of  different  min- 
erals, and  may  even  rest  as  a  mantle  on  the  crystals  which  line 
cavities.  It  is  at  times  the  less  soluble  portion  left  by  the  de- 
cay and  removal  in  soluticjn  of  wall  rock  (residual  clay),  at 
times  the  comminuted  material  resulting  from  the  friction  of 
moving  walls  (attrition  clay),  and  again  it  may  be  taken  up  by 
currents  and  redeposited  from  bodies  of  the  first  two  sorts. 
Such  layers  of  clay,  being  well-nigh  impervious  to  water,  may 
have  exercised  an  important  inllnence  in  directing  the  subterra- 
nean circulations.' 

1.05.(14.  J*itic]ies,  Sivells.  and  Lateral  Enrirlunents. — The 
s\v(>lls  and  pinches  of  veins  have  been  referred  to  above  and  ex- 
jilained.  Aside  from  these  thicker  portions  of  the  ore,  it  is 
often  seen  that  the  richer,  or  even  the  workable  bodies  follo'.v 
certain  nv  ."e  or  less  regular  directions,  forming  so-called 
"chutes."  They  probably  correspond  to  the  courses  taken  and 
followed  b}-  the  richer  solutions.  J.  E.  Clayton  observed  that 
tliey  follow  the  directions  of  the  sli])s,  or  stri;e.  of  the  walls 
rather  more  often  than  not.  and  in  the  West  this  disposition  or 
[tendency  is  called  Clayton's  law.  Chute  is  sometimes  spelled 
'shoot"  or  "shute."  Chimney  and  ore-cour.so  are  synonyms 
I  of  chute.  Bonanza  is  used,  especially  on  the  Comstock  Lode, 
[to  indicate  a  localized,  rich  body  of  ore. 

Lateral  em'ichments  are  caused  by  the  spreading  of  the  ore- 
i  bearing  currents  sidewise  from  the  vein,  and  often  along  par- 
[tieular  beds  of  rock,  which  they  may  re])lace  more  or  less  with 

'  See  citation  from  Becker  ou  the  Comstock  Lode,  2.11.19. 


50 


KKMP'S  OliE  DEPOSITS. 


ore.  Bods  of  limestone — it  may  be  (jiiito  thin,  Avhen  in  a  series 
composed  of  sbMlesorsjindstones— are  favorite  precipitants,  and 
from  Hiicli  lateral  eidargenicMit  tlie  best  returns  may  be  (j1i- 
taiued,  Tbe  valuable  ore  liodies  of  Newman  Hill.  n(>ar  Kicn. 
Colo.,  whose  interesting  descriptions  by  J.  B.  Farisb  and  'J\  A. 
Rickard  have  already  been  several  times  cited,  are  foimd  as 
lateral  enrichments  alonj^  a  bed  of  limestoiie  less  than  three 
fi'et  thick  and  (Mubedded  in  shales.  Above  the  limestone  tlif 
veins  practically  (hmisc,  as  tbe  fissures  become  tij^bt  in  a  series 
of  sandstones  and  shales.  Lateral  enrichments  may  (dosel,y  re- 
semble bedded  deposits  if  the  supply  fissures  are  relatively 
small,  but  it  is  generally  safe  to  infer  the  presence  of  sujjply 
conduits,  although  they  may  be  obscure.  The  Potsdam  ores  of 
the  Black  Hills  are  good  illustrations. 

1.0"). ().').  CJkiikjcs  in  C'hdriufer  of  Vein  FiUiiif/. — In  dis- 
cussing the  intlut'nce  of  wall  rock  the  changes  that  occur  in 
veins  were  brieily  mentioned.  But  even  where  the  walls  re- 
main xmiform  there  is  always  variation  in  contents,  and  of 
course  in  value,  from  point  to  ])oint.  Ore,  gangue.  horses,  and 
walls  alternate  both  longitudinally  and  iu  de])t]i,  and  sucli 
changes  must  be  allowed  for  and  averaged  by  kee})ing  explora- 
tion well  in  advance  of  excavation.  Even  a  series  of  parallel 
veins  may  i\\\  prove  fickle.  In  illusti-ation  of  the  above  the 
Marshall  tunnel  of  Georgetown,  Colo.,  may  be  cited.  It  i-iit 
twelve  veins  below  their  actual  workings,  and  every  one  was 
ban-en  at  the  tunnel  though  ])r()(bictive  above.' 

1. ().■).(»().  Si'((>ii<l(ir/j  AHeral ion  of  the  Mincriils  in  Voius. 
—It  has  already  been  stated  that  the  chief  ore  minerals  in  vein 
fillings  are  suljdiides.  Where  the,-;e  lie  above  the  line  of  ]ioi'- 
maueut  subterranean  water  they  are  exposed  to  the  oxidizinirj 
and  hydrating  action  of  atmospheric  waters,  wbicli,  falling  on 
the  surface,  percolate  downward.  Tb(>  ores  are  thus  subjt'cttMl 
to  alternating  soakiiigs  and  dryings  which  encourage  altera- 
tion. The  sulphides  change  to  sulphates,  carbonates,  oxides. 
or  hydrous  forms  of  the  same,  and  the  metallic  contents  are  in 
part  removed  in  the  acid  waters  which  are  also  formed.  Py- 
rite.  Avhich  is  the  most  widespread  of  the  sulphides,  beconn"- 
limonite,  staining  everything  with  its  cbar.icteristic  celer, 
Galena  becomes  cerussite  or  anglesite.     Blende  affords  <alii- 

*  J.  J.  Stevenson,  Wheeler's  Siuvoy,  Gcoloijt/.  Vol.  III.,  p.  351. 


ON  STRUCrUUAL  ?'EATURES  OF  MIXICRAL    VEINS,      51 

niino  and  sniithsonito.     Copper  ores,  of  wliicli  tho  umial  one  is 
clialcopyrite,  chanj^o  to  nialacliito.  azurito,  clirysocolla,  ciqaMte, 
and  iiu^laconite,  and  to  tho  suli)liide,  clialcocite.    The  silver  sul- 
phides afford  cerargyrite.    The  rarer  metals  alter  to  correspond- 
ing comjiounds  of  less  frecpiency.     These  vipper  portions  are 
also  more  cellular  and   porous,  being  at  times  even  earthy. 
Tlie  rusty  color  from  tho  presence  of  limonite  often  marks  the 
outcrop  and  is  of  great  aid  io  the  prospector.   It  has  been  called 
the  iron  hat,  or  gossan.     This  feature  has  important  economic! 
bearings.     Tho  ciiaracter  of  ores  may  entirely  change  at  a  defi- 
nite  point  in  depth,  and  the  later  products,   if  not  lower  in 
j;ra(le,  as  is  often  the  case,  may  demand  different,  perhaps  more 
(litiKcult,  modes  of  treatment.     Oxidized  ores  are  the  easiest  to 
smelt,  and  the  desirability  of  careful  exploration  before  indulg- 
ing in  too  confident  expectations  may  be  emphasized.     As  exam- 
ples, the  Ducktown   copper  deposits    (See  Example    1<'>),    the 
Leadville  silver  mines  (Example  ;5()).  the  southwest  Virginia 
zinc  deposits  (Example  'i.(\),   tl)3  copper  and   silver   veins  at 
Butte.    Mont.    (Pjxample    17),   and    others    in    Llano  County, 
Texas  (Exam])le  1i/>),  may  be  cited.     At  Ducktown    a   con- 
siderable thickness  of  clialcocite,  melaconite.  and    carbonates 
accnnudated  just  at  the  waterline  and  abruptly  changed  to 
low-grade,  unworkable  pyrite  and   chalcop3-rite  helow  it.     At 
Bonsacks,  near  Roanoke.  Va.,  very  rich,  easily  treated, earthy 
limonite  and  smithsonite  (odto  40  per  cent,  zinc)  ])assed  into  a 
let'ra.'tory.  low  grade  (IT)  to 'JO  percent,  zinc),  intimate  mixture 
of  blende  and  pyrite.     Excavations   in   di'V  districts  may  not 
veaeli  the  ^vater  line  for  great  depths.     Thus  at  Eureka,  Nov., 
in  the  rainless  region  of  the  Great  Basin,  the  oxidized  ores  con- 
tinue to  i)(»0  feet  or  more. 

It  is  worthy  of  remark  in  this  connection  that  possibly  some 
»le|iosi1s  of  oxidized  ores   may  have   been  formed   originally  as 
isiich.     Wendt  has  argued  this  tor  the  copper  mines  of  the  Bis- 
hee  district,   Arizona;  but  in  this  case  recent  ex|)loration  has 
er^tablished  the  former  presence  of  sulphides.     (See  Example 
1'.'"^. )    If  oxidized  ores  are  now  found  below  the  Avater  line,  it 
niay  indicate  a  depression  of  the  rocks  from  a  previous,  higher 
hiosition.     R.  V.  Hills  has  1>rought  out  a  very   interesting  in- 
stance of  the  concentration   of   g(,)ld   and  silver  in  the   lower 
part  of  the  oxidized  zone,  or  at  least  at  a  considerable  depth 


1    1 


52 


K /'J MP'S  OHM  JfKPOSri'S. 


below  tho  outcrop.  Tho  u[>[ivy  iiortiou  of  tlio  voin,  in  this 
case  with  a  (jiiartz  gau^ue,  was  iinpovoriHhcd.  The  gold  is 
thought  to  have  been  carried  down  in  Holution  with  ferrous 
and  ferric  sulphates,  which  were  decomposed  by  feldspar. 
while  tho  precious  metal  was  thrown  down.  The  ore  boiiics 
lie  in  the  Sunnnit  district,'    Ki(^  Grande   County,    Cohmido. 

1. ()').()?'.  The  waters  of  mines  which  have  opened  up  and 
exposed  sulphides  to  oxidation  are  often  charged  with  sul- 
phuric acid  and  even  metallic  salts.  This  is  especially  true  of 
mines  in  copper  sulphides,  and  the  pmnps  are  much  corroded. 
In  instances  considerable  metallic  copper  has  been  removed  ])y 
])assing  the  mine  drainage  o\er  scrap  iron,  as  at  Ducktown, 
Temi.,  and  as  has  been  introduced  at  Butte,  i\lont.  IVliue 
timbers  have  been  preserved  very  long  jjcriods  by  the  de})osi- 
tion  of  copper  on  them,  because  of  their  reducing  action  on  the 
solutions.  Pumps  and  timbers  placed  by  the  Romans  in  the 
]'io  Tinto  mines,  in  Spain,  are  still  in  good  preservation. 
p]ven  gold  has  been  detected  in  Australian  mine  waters.'^ 

1.0.5. OS.  Kli'ciricdl  .lr//r////.— Among  the  writers  of  ilfty 
or  sixty  years  ago.  electrical  or  galvanic  action  was  a  favorite 
theoretical  precijiitant  of  ores  in  veins,  and  careful  experi- 
ments were  made  in  Englam  lud  Germany  to  detect  it.  l^y 
connecting  the  o])posite  ends  of  a  vein  with  a  wire,  in  wliicli 
was  a  galvanometer,  the  attempt  was  made  again  and 
again  to  establish  the  existence  of  galvanic  action.  At  times 
the  results  gave  some  grounds  for  belief,  but  at  others  they 
were  contradictory  or  uncertain,  so  that  no  very  definite  or 
reliable  conclusions  were  established  Other  experiments 
were  made  in  German^^  about  1H44,  by  lioich,  while  lately 
quite  elaborate  investigations  have  been  carried  out  by  Dr. 
Carl  Barus  on  the  C^omstock  Lode,  and  at  Eureka,  Nev. 
Great  difficulties  are  met  in  preserving  the  necessary  insula- 
tion throughout  the  wet  and  devious  imderground  workings. 

""^R.  C.  Hills,  Proe.  Colo.  Scl  Sue.  Vol.  I.,  p.  ;«;  S.  F.  Eiuiiious,  (juot 
ing  Hills,  EiKjiiircn'iig  (iiid  Miniiuj  Jonriial,   June  9,  1883. 

For  a  very  complete  discussion  of  the  alteration  of  ore  deposits  above 
the  ground  water  and  of  the  fonuation  of  gossan  niinei'als,  see  R.  A.  F. 
Penrose,  Jr.,  "The  Sui)ertieial  Alteration  of  Ore  Deposits,"  Joni'mil  of 
Grohxjy.   II.  >28S,  181)4. 

'  See  School  of  Mines  Quarterly,  Vol.  XI.,  364,  for  review  of  literature 
bearing  on  this  subject. 


Oy  .STIlUCTlli'M.    FEATillES  or  MIMHIM.    Vi:iX8.       b'.\ 


aiiu  amid  siu'li  Hurroundiiif^H  in  (Ictcclii)^  tlio  ciirrontH,  wliicli 
would  1)0  iioccHHurily  small.  With  IJariiH  tlio  llicsiH  wmh  not 
iiloncto  oMtublinh  u  galvanic  action,  such  as  might  Ikwi  precipi- 
tating agency,  but  hIho  to  observe  what  etT'ect,  if  any,  was  ex- 
erted by  tne  intervention  of  an  ore  body  on  the  norn)al  terres- 
trial currents.  Had  this  latter  been  provcil  of  sufficient  aniomit, 
the  existence  of  such  bodies  might  bo  indicated  by  plotting 
electrical  observations.  While  in  some  nvspects  of  interest,  the 
results  of  ])r.  ]5arus  are  not  very  decisive,  and  this  lino  of  in- 
vestigation is  hardly  to  be  considered  a  promising  one.  The 
importance  attadjed  to  it  in  former  years  may  be  illustrated  by 
tlu'se  words  of  De  hi  Beche,  one  of  the  ablest  of  English 
writers,  in  18:50.  Speaking  of  v(Mns  in  general,  after  discussing 
those  of  Cornwall  in  i)articular,  he  says:  "Mineral  veins  result 
from  the  filling  of  fissures  in  rocks  by  chemical  deposits,  from 
substances  in  solution  in  the  fissures,  such  deposits  being 
greatly  due  to  electro-chemical  agency."  The  influence  of  ter- 
restrial magnetism  upon  the  distribution  of  mineralized  dis- 
tricts has  l)een  urged  b}'  T.  F.  Van  Wageuen,  who  endeavors 
to  show  for  the  Cordilleran  region  of  North  America  that  the 
productive  areas  lie  along  mean  magnetic  curves  and  that  they 
are  separated  by  barren  belts.  The  productive  belts  are  thought 
to  converge  at  the  magnetic  pole  of  the  earth  north  of  Hudson 
Ray.' 

'  Tlieo.  V.  Van  Waj^eiieii,  "System  in  the  Loeution  of  Mining  Districts," 
■SV/aioi  of  Mines  Quarterly,  January,  IS'.KS,  p.  lou. 


m 


CHAPTER  VI. 

THE    CLASSIFICATION    OP    ORE    DKl'OSITS— A  liEVIEW    AND    A 
SCHEME  BASED  ON   OKKJIN. 

1.0(5.01.  lu  the  clarfHilioutiou  of  ore  deposits  the  same  systo- 
niatic  arrangement  is  not  to  bo  expected  as  in  the  grouping  of 
plants,  animals,  or  minerals.  Ore  (loposits  haA'o  not  tiie  under- 
lying attinitiesand  relationships  of  living  organisms  nor  of  deri- 
nite  cht'mical  compounds.  The  series  of  ohjects  is  too  diverse. 
and,  in  the  nature  of  the  case,  the  standards  of  appeal  must  be 
different.  The  subject  is,  however,  one  of  great  practical  impor- 
tance as  well  as  of  great  scientific  interest.  A  vocabulary  of 
intelligilile  terms  is  indispensable  for  description  and  compari- 
son, and,  under  our  mining  laws,  often  for  valid  titles,  while 
as  a  vehicle  for  the  spread  of  knowledge  and  reasonable  con- 
ceptions regarding  these  phenomena,  its  importance  cannot  be 
overestimated. 

l.()(i.()3.  All  schemes  of  classification  rest  on  these  princi- 
ples: form,  origin — or  the  genetic  principle  (incluaing  method, 
relative  time  of  origin  as  contrasted  with  the  walls,  etc.) — state 
of  aggregation,  and  mineral  contents.  Ot  these,  the  principle  of 
form  ia  usually  esteemed  the  weightiest,  and  is  given  the  great- 
est prominence,  partly  because  it  has  been  thought  to  be  the 
one  most  closely  affecting  exi)loitation,  and  })artly  because  it 
involves  less  that  is  or  lias  been,  up  to  very  recent  times,  more 
or  less  hypothetical.  Yet  form  is  largely  fortuitous,  and  it  has, 
of  course,  no  law,  while,  with  sufficient  knowledge,  the  genetic 
principle  is  the  one  giving  a  far  more  thoroughly  scientific 
hasis.  Everyone,  in  opening  up  or  searching  for  an  ore  body, 
must  be  influenced  by  some  hypothesis,  either  of  shape  or  of 
origin.  It  is  the  conviction  of  the  writer  that,  with  all  our  de- 
ficiencies of  knowledge,  the  genetic  principle  is  also  the  best 
guide,  even  in  practical  development. 


CLASSIFICATION  OF  OliK  DMI'OSITS. 


55 


I. (1(1. ().'{.  Very  early  ill  tlio  (Icvt'Iopiiicnt  of  mining  litcra- 
tiin^  llio  (liMtiiK'tion  was  ina<lo  betweuu  those  oro  InxlioH  wliicli 
iirc  pamllol  to  tlie  Htratification  uihI  tlioso  which  break  iiiicon- 
t'()rnial)ly  acroHS  it.  Tin's  took  placH*  loiij^  hcforo  tho  opodi-iimk- 
\\\\f  tiiiMj  of  Woruer,  and  livon  before  the  croncoptiou  of  tho  reiu- 
tive  a;^eK  of  strata  had  hci^n  at  all  generally  }j;ras|)t'd.  Tlnm 
iUiKinf^  tiie  (i(M'inans  avo  find  tlio  torins  "La|i;('r"  and  "Fl(»t/o"' 
(III  tho  one  aide,  bcniig  sot  oft'  in  contrast  to  "(Jang"  (vein) 
on  tho  other.  Werner,  writing  in  17tH,  quotes  Von  Oppol's 
(h.stinctions  between  Flcitzo  (strata  beds)  and  (ii'mge  (veins), 
wliich  were  ])uhlishod  in  17H>;  but  without  doubt,  as  mining 
tonns.  they  go  nuK^h  further  l)ack.  Beyond  this  simple  indica- 
tion of  tho  views  of  tho  older  writers,  no  attemjjt  will  ho  made 
here  to  (piote  authorities  earlier  than  1850.  This  is  justiliable. 
hecause  tho  imjiortant  works,  like  De  la  Beche's  (HeaUuni  of 
('orinrdll  and  Dcron,  and  H'enwood's  Mcfdllifcrons  Depo.sHs 
of  Connrdll  and  Devon,  are  rather  discussions  of  veins  than 
systematic  attempts  at  classification. 

1.0(1.01.  In  Appendix  1.  will  be  found  the  principal  schenu's 
of  classilication  which  have  thus  far  been  suggested.  They  air 
grouped  according  to  certain  relationships  and  similarities  thai 
run  through  them.     The  scheme  here  given  finds  its  natiii;.. 


'  LiiK<!r  and  Flot'/e  are  difftcult  to  render  into  Enj^lisli  while  retainirf; 
tlioir  native  shades  of  nieaninf?  Tlie  hiter  writers  in  Uennany  (Serlo, 
(lat/cliniiiiiii.  Von  (iroddet^k,  K(">ldor)  dcliiK^  tlinni  as  Ihmii";  iiitcrlicddcd 
liddics,  ciicli  hiter  tliaii  tlie  foot  wall  in  lorniatiou,  and  oldci'  than  tlir 
liaiij^inf;;:  and  that  Lager  are  much  more  limited  in  liorizontal  extent 
tliiiii  Kh'itzc  R.  Walincr  shows,  liowever,  in  tin*  Ben/.-  ii.  lli'it  ZiihiiKj, 
.l:ia.  'J,  IHiil,  ]).  1,  that  writers  in  tlie  earlier  part  of  tho  century  did  not 
entirely  re.strii't  the  term  Lager  as  regards  age  relative  to  the  foot  and 
ii;m;;iiig,  but  apiilied  it  to  ore  bodies,  which  follow  th(^  genci'al  bedding, 
iiltiiough  they  may  have  been  introdmred  much  later  than  the  formation 
of  tlie  walls.  Thus  the  f  recpient  occurrence  of  lead  ores  in  litnestone  along 
••ertain  beds  (.southeast  Missouri  for  exami)le)  would  be  called  Lager. 
We  would  jxpply  the  terms  impregnation,  or  dissemination,  or  betl  vein,  to 
.such.  I'lntze  we  would  <'all  stratmn.  and  Lager,  as  delined  by  the  later 
authors 'bed"  or '•seam."  Werner,  for  instance,  in  liis  clas.sili(ration  of 
tho  rock  formations  of  the  globe,  made:  I.  Urgebirge  (Primitive.  Primary, 
t'ti'.,  li;iving  no  fossils)  II.  Secondary,  subdivided  into  A.  T^eber- 
KanRsgybirge  (transitional,  more  or  less  metamorphosed  sediments,  but 
fo^siiitVious).  B.  Flotzgebirge  (unaltered  strata).  From  this  the  mean- 
in,:,'  of  Flotz  may  be  grasped.  By  contrast,  a  magnetite  lens  is  a  good 
illustration  of  Lager. 


56 


KEMP'S  ORE  DEPOSITS. 


place  as  No.  17,  and  at  the  time  that  it  was  first  prepared  it  w.is 
UL^ijue  in  being  a  purely  genetic  one,  except  that  one  by  F.  1). 
Power,  which  appeared  in  Melbourne  the  same  3'ear,  ran  along 
the  same  lines.  The  literature  of  the  next  few  years  proved, 
however,  that  the  subject  whs  active  in  many  minds,  and  other 
schemes  were  independently  published  in  dilferent  parts  of  tht 
world,  which  were  conceived  from  the  same  })oint  of  view.  In 
the  one  below,  the  four  important  methods  of  origin,  viz.,  the 
igneous,  the  methods  of  precipitation  from  solntion  or  by  de{)()- 
sition  from  suspension  or  by  deposition  as  residual  concentra- 
tio/is,  are  made  fundamental  and  then  the  ore-bodies  belonging 
under  each  are  referred  so  far  as  possible  to  well-recognized  and 
familiar  geological  phenomena.  The  close  analog}-  of  this 
grouping  in  some  of  its  particulars  to  the  commonly  a(.ce})ted 
classilication  of  I'ocks,  will  beat  once  apparent,  and  our  general 
knowledge  of  rocks  may  be  used  to  throw  light  uj)on  the  ore 
deposits,  but  the  latter  with  the  exception  of  a  few  involving 
iron,  are  never  in  sufficient  amount  to  be  consideied  i)arti?nlar 
forms  of  rock,  in  and  of  themselves.  The  scheme  is  also  the 
natural  result  of  the  general  exposition  of  the  subject  in  the 
preceding  pages,  which  have  consistentl}'  led  up  to  it.  Certain 
obscure  ore  bodies,  whicli  are  not  well  understood,  receive  spe- 
cial mention  after  the  general  discussion. 

l.dC.or).     J.  F.  Kemp,  lS<)-2.     Revised    from  the   School   of 
Mines  Qnarterly,  Noveml)er,  1  <'.^2. 

I.  Of  Igneous  Origin.  Excessively  basic  develop- 
ments of  fused  and  cooling  magmas.  Peridotite, 
forming  iron  ore  at  Cumberlan(',  Khode  Ish.nd.' 
Titaniferous  magnetite,  Jacu})iranga.  Brazil  r  in 
Minnesota  gabbros;'  in  Adirondack  gabl)ros;'  in 
Swedish  and  Norwegian  gabbros.'  Nickeliferous 
pyrrhotite."    Chromite.'     Conuidum.' 

'  M.  E.  Wadswortli,  Bnll.  illiis.  Comp.  ZooL,  1H80,  VII, 

"  O.  A.  Derby,  Aina'.  Jour.  ScL.  Ap-il.  ls!U. 

'  N.  H.  Wincliell.  Tf'iith  Ann.  Rep  Miiui.  (Uol.  Sm-rnf.  pp.    80-R3.  Bull 
VI.  of  saiMe  Kiirvt'3',  ]>.  l'?r». 

*  J.  F.  Keuip.  Bitli.  Geol.  Soc.  Aiiicr.,  V.  2-22.  Vm.  XIX.  Auiiiml  Rip. 
Dir.  U.  S.Gfol  Smiri/.      (In  i)mss,  ]Miiifl.,  IMiiit.) 

'  .1.  H.  ij.Vo'^t.  Geol.  Forci}.  i.  Stoc.clioliii  FoHiowl.  XIII.,  lH).  'Shiy,  1S!H. 
En^'lisli  ahstract  and  review  by  J.  J.  H.  Teall,  Geol.  Mag.,  February,  l".'-' 
See,    ,o  r    '   'lir.  fib'  Prdliii.sche  Geolor/ie.  1,4. 

'  See  relV.eiices  luider  |iaraKriipJi  l.Ofi.OH  below. 

'  See  references  under  |tara}^ra;)li  1.0(>. ''1. 


CLASSIFICATION^  OF  ORE  DEPOSITS. 


57 


11,   Deposited  from  solution. 

1.  Surface  precipitations,  often  lorming 
beds  and  caused  by — ■ 

(a)  Oxidation.  Bog  ores.  Ferruginous  oolites, 
as  in  some  Clinton  ores.^ 

(&)  Sulphurous  exhalations  from  decaying  or- 
ganic matter,  etc.     (Pyrite.) 

(c)  Reduction,  chiefly  by  carbonaceous,  organic 
matter.      (Pyrite  from  ferrous  sulphate.) 

{d)  Evaporation,  cooling,  loss  of  pressure,  etc. 
Hot  spring  deposits,  as  at  Steamboat 
Springs,  Nev." 

{e)  Secretions  of  living  organisms.  (Iron  ores 
by  algJD."' 

Note. — These  same  causes  of  precipitation  operate  in  sub- 
terranean cavities,  although  not  again  specially  referred  to. 

2.  Disseminations  (impregnations)  in  par- 
ticular beds  or  sheets,  because  of — 

(a)  Selective  porosity.     (Silver  Cliff,  Colo.,  sil- 
ver ore   in  porous  rhyoiite.*      Amygda- 
loidal  fillings  as  in  copper-bearing  amyg- 
daloid.    Keweenaw  Point,  Mich. ;   Santa 
Rita,  N.  M."     Impregnations  of  porous 
Sandstone  as  at  Silver  Reef,  Utah.* 
(6)  Selective  precipitation  by  calcaredus  matter. 
Potsdam  or  siliceous  gold  ores.   Black 
Hills,  S.  I).' 

3.  Filling  joints  caused  by  cooling  or  dry- 
ing (^Mississippi  Valley  gash  veins  in 
part). 

'  r   1{   Sniytli,  Jr  ,  Amer.  Jour.  Sci.,  June,  1892,  p.  487. 

Mi  i'.  Becker,  MoTwgvdph  XHL,  U.  S.  G,ol.  Siarc)/,  p\y  XU,  4«8;L:uir, 
.liiii.  ill  s  Mines.  IHChi,  p.  421;  ,J.  Lecoute,  Aiiwr.  Jour.  Sci.,  June,  188:5,  p. 
4i>4,  ^uly,  p.  1;  W.  H.  Weed,  iih'm,  August.  18!)1,  j).  I(!f5. 

"Sjo^'i-un,  Brry.-  nnd  llhtt.  Zcit.,  ISO."),  p.  110. 

*  Clark,   Enijiuriri)tif  and  Mining  Journal,  Nov.  2,  1878,  p.  314. 

•A.  l'\  Weiult,   Tran.i.  Amer.  Inat.  Min.  Enij.,  XV.,  27. 

"CSl.  Rolker,  idem,  IX.,  31. 

'  J.  T).  Irving.  Anrals  N.  Y.  Acad.  Sci.,  XII.  Part  II,  1899.  Other  cita- 
ti'm.swill  befoimd  under  2,01.03. 


68 


KEMPS  ORE  DEPOSITS. 


4.  Occupyiug  chambers  (caves)  in  lime- 
stone.    (Cave  Mine,  Utah.* ) 

5.  Occupying  collapsed  (brecciateil)  beds, 
caused  by  solution  and  removal  of  sup 
port,  ur  from  dolomitization  of  lime 
stone.  (Southwest  Missouri  zinc  depos- 
its. "^  Occujjying  cracks  at  Monoclinal 
bends,  Anticlinal  summits.  Synclinal 
troughs,  often  with  replacement  of  walls. 
(Gash  veins  in  part;  galena  deposits 
at  Mine  la  Motte,  Missouri;  zinc 
blende  deposits  in  the  Saucon  Valley, 
Pennsylvania,'')      Elkhorn  Mine,  Mont. 

G.  Occupying  shear-zones,  or  dynamically 
crushed  strips  along  faults,  whose  dis- 
placement may  be  slight,  closely  related 
to  No.  s.     (Butte,  Mont.)* 

7,  True  veins  filling  an  extended  fissure, 
often  with  lateral  enlargements.  See 
also  under  5. 

8,  Occupying  volcanic  necks,  in  agglom- 
erates. (Bassiok  Mine,  near  Rosita, 
Colo.)^ 

9,  Replacements  in  troughs  of  some  im- 
pervious rock  or  rocks.  (Lake  Superior 
hematites.)'' 

10.  Contact  deposits.  Igneous  rocks  always 
form  one  wall,    Fumaroles.     (Greiseii.) 


'  J.  S.  Newberry,  School  of  Nines  (Jnartcrli/,  Murcli,  ISHO.  Hee  also  J. 
P   Kimball,  on  Santa  Eulalia,  C'bilmabna,  Anici:  Join:  Sri.,  II.,  xlix.  Uil. 

"  B^  L.  Clerc,  Lead  and  Zinc  Ores  i)i Southwest  Missouri  Mines,  Ciirtha'^^. 
Mo.,  1887;  A,  chmidt,  Missouri  Oeol.  Survej/,  1HT4,  p.  384.  vSee  later 
papers  cited  under  Example  25. 

»  F.  L.  Clerc.  Minend  Jiesonrces,  1883,  p.  '.W\  ■  11.  S.  Drinker,  Trans. 
Ainer.  Inst.  Min.  Eiaj.,  I.,  !5(JT. 

♦  S.  F.  Emmons,  Trans.  Amer.  Inst.  Min.  Emj.,  >:VI.,  4!);  VV.  P,  Bhike, 
Idem,  XVI.,  (m.     Bntte  Special  Folio.    U.  S.   (,'col.  Snrrci/. 

»  C.  W.  Cross,  Proc.  Volo.  Sci.  Soc,  lsi)(>,  p.  2»)!».  S,  F.  Emmons,  A' 1 7/ 
Rep.  U.  S.  Geol.  Snrv.,  Part  II.,  p.  4:50. 

•  C.  R.  Van  Hise,  A)uer.  .Jour.  Sci..  February,  1892,  p.  lift.  Monoyr'.iih 
XXVIII  U.  S.  (ieol.  Surv. 


■^JJ^-T 


CLASSIFICATION  OF  ORE  DEPOtlTS. 


59 


ll\V!l,\> 

also  .1 


er,  Tnois. 
p.  Bliike, 
US,  A'l'/' 
ojioyi'l''' 


11.  Segregations   formed    in    the  alteration 
of  igneous  rock.     (Cbroniite  in  serpen- 
tine.) 
III.  Deposited  from  Suspension      Residual  Deposits, 

1.  Metalliferous  Sands  and  Gravels, 
whether  now  on  the  surface  (placers, 
magnetite  beach  sands),  or  subsequeutl}^ 
buried.  (Deep  gravels, magnetite  lenses?) 

2.  Residual  Concentrations,  left  by  the 
weathering  of  tlie  matrix.  (Iron  Moun- 
tain, Mo.,  hematite  in  part.') 

LOG. 06.  It  is  believed  that  under  the  above  heads  are  in- 
cluded all  the  forms  of  ore  bodies  which  co^  'itute  well-recog- 
nized and  fairly  \.  ell-understood  geological  phenomena.  To 
these  categories  year  by  year  we  are  enabled,  by  the  results  of 
extended  and  careful  investigation,  to  refer  many  that  have 
been  obscure.  A  number  of  familiar  terms  for  ore  bodies  in 
mining  literature  fail  to  appear,  but  are  mentioned  in  the 
classiHcations  quoted  from  other."  (See  Appendix  I.)  Many 
of  these  refer  only  to  form,  and  geologically  considered  are  only 
convenient  admissions  of  ignorance  as  to  origin.  Some  other 
ore  bodies  whose  methods  of  origin  are  involved  in  the  processes 
of  regional  metamorphism  are  placed  b}'  themselves  further  on. 
The  explanations  of  them  are  as  yet  hy])othetical.  A  few  com- 
ments on  the  scheme  may  now  be  added,  although  in  the  main 
it  explains  itself. 

1.0<;.07.  I.  The  writings  of  Lagorio,  Iddings,  Rosen buscli 
and  others,  regarding  the  development  of  rocks  from  fiised 
ni;i,t;inas.  have  emphasized  the  fact  that  the  laws  of  solution  do 
not  fail  to  a})])ly,  because  the  magmas  are  raised  to  very  ele- 
vated temperatures;  and  that  they  hold  good  for  fused  rock 
i  wisely  as  for  heated  water  or  anj'  other  solvent.  Other  laws 
ot  physical  chemistry  anu  of  thermodynamics  have  also  been 
recognized  by  many  as  fundamental  to  the  true  understanding 
o{  the  reactions,  but  the  subject  is  a  difficult  one,  and  our  knowl- 
edge is  as  yet  incomplete.  The  reactions  are  complex  and 
ot'cur  at  such  elevated  tem})eratxu"es  as  to  render  observation 
difiicult.     The  magmas  known   in  Nature  are  of  endless  va- 


R.  Puinpcliy,  BnU.  (icol.  Soc.  Amcr.,  II.,  p.  220. 


GO 


KEMP'S  ORE  DEPOSITS. 


riety,  and  involve  a  number  of  bases.  Just  which  portion  is 
solvent  and  which  is  dissolved  matter  may  not  always  be  clear, 
nor  do  we  cei'tainly  know  the  actual  state  in  which  the  ele- 
ments exist  at  these  high  temperatures,  nor  the  iiiMuence  of 
electrical  currents  or  still  more  obscure  forces.  Nevertheless, 
we  do  know  that  as  the  magma  cools  from  a  perfectly  fluid 
condition  the  first  minerals  to  separate  are  those  which  first. 
under  the  diminishing  temperature  (and  perhaps  pressure) 
reach  a  state  oi  saturation  and  must  therefore  crystallize.  If 
this  is  expressed  in  the  terms  of  tliermodynamics,  we  may  say 
that  those  compounds  will  first  form  Avhich  liberate  the  most 
heat  in  crystallizing,  and  so  on  down  to  complete  solidification. 
Usuall}'' the  order  is  that  described  in  paragraph  3. 013. 05,  but 
mass  action,  brought  about  by  the  superabundance  of  one  ele- 
ment or  another,  may  affect  the  oi'der,  and  the  variability  of 
composition  shown  by  igneous  rocks  is  also  a  serious  factor. 

Students  of  rocks  have  verj'  generallj-  reached  the  conclu&it)u 
that  a  great  jmrent  magma  which  stands  molten  for  long  pe- 
riods in  the  earth  will  break  up  into  ditfereut  com})onent  or 
fractional  magmas  before  any  mineral  crystallizes.  The  frac- 
tional magmas  b}'  successive  eruptions  afford  various  different 
tj'pes  of  rockH  of  greatly  contrasted  composition.  The  process 
is  called  differentiation,  and  it  is  of  interest  in  this  connection 
as  showing  In  a  general  way  the  tendency  of  fused  rock  masses 
to  break  uj)  and  vary. 

All  the  above  theoretical  considerations  throw  light  on  the 
formation  of  the  igneous  ore  bodies. 

l.dO.OH.  The  first  ore  bodies  to  which  an  igneous  origin  w;i3 
attributed  in  the  past  were  those  portions  of  a  ^^asic  intru- 
sion, such  as  a  peridotite  or  a  gabbro,  whicii  were  so  enriched 
with  magnetite  as  to  become  an  ore.  The  magnetite  is  almo.st 
always  titaniferous  and  may  indeed  be  ilmenite.  The  classic 
occurrence  of  this  tyjie  is  Taberg,'  in  Sweden,  whe^e  a  great 
boss  of  basic  igneous  rock  1..5  kilometers  (1.3  miles)  Ioiilc. 
0.5   kilometer  (0.+  mile)  broad  and  loO  meters  (400  ft.)  higli  is 

'  A.  Sjogren,  Ueber  das  Eisenerzvorkommen  von  Tab^Tg  in  Sma!:iiid. 
Grol  Foreii.  in  Stockholm,  Forliandl,  III.,  42-62, 187(5,  and  VI.,  1882;  Nenes 
Juhrbwh.  ISTC,  484. 

A  E.  Tornobolnn,  Om  Taberg  i  Smaulaiid  och  ett  par  dermed  anal'^a 
jerninahnforekomster.  Idem,  V.  fil(Mili),  1881.  Neues  Jahrbnch,  l>^'i, 
II.,  iW 


CLASSIFICATION  OF  OliH  DEPOSITS. 


61 


found  intriuled  in  granite-gneiss,  with  its  long  axis  parallel  to 
tlie  foliation.  In  the  central  ])art  of  the  hoss  is  found  the  ore, 
a  mixture  of  titauiferous  magnetite  and  olivine,  hut  the  hoss 
shades  from  ore,  outwnrdly,  hy  the  increase  of  feldspar  to  the 
variety  of  gahbro,  called  hyperite  in  Sweden.  In  the  hasic  core 
and  acidic  rim  the  boss  differs  from  most  iutiusions,  because  the 
latter  shade  from  acidic  cores  to  basic  rims.  The  Cxmiberland 
ore,  Rhode  Island,  forms  a  boss  of  titauiferous  magnetite 
mingled  with  olivine  and  pyroxene.  It  is  much  like  that  of 
Taberg.  The  ore  of  fcr-czil  is  strongly  titanit'erous,  but  occurs 
ill  basic  rocks  with  nepheline,  and  much  the  same  is  true  of 
Aluo,  Sweden/ where  nepheline  syenite  is  the  geological  asso- 
ciate. In  the  Adiroudacks,  and  in  Minnesota,  Quebec.  Wj'o- 
iiiing  and  Norway,  huge  masses  of  quite  pure  titauiferous 
magnetite  occur  in  anorthosite  gabbros.  As  a  }teculiar  phase 
of  the  Cortlandt  series  of  gabbros  on  the  Hudson  River,  near 
Peekskill,  there  are  richly  aluminous,  but  feebly  titauiferous 
(u-es  which  consist  of  spinel,  corundum  and  titauiferous  mag- 
netite. At  Roiitivara,  Sweden,"  practically  the  same  aggre- 
gate has  been  found. 

l.lKi.OU.  In  addition  to  the  igneous  magnetites,  chroinito 
lias  l)een  met  by  Vogt  in  an  outcrop  of  unaltered  peridotite 
within  the  Arctic  circle,  in  Norwaj-,'' and  J.  H.  Pratt'  attri- 
butes the  same  method  of  origin  to  the  chroinite  of  North 
Carolina,  although  hitherto  chromite  in  serpentine  has  usually 
been  considered  a  segregation  produced  during  the  weathering 
of  rocks  which  ])Ossess  chrome-bearing  silicates.  Corundum  is 
now  recognized  in  a  few  places  as  a  result  of  crystallization 
from  fusion.  The  special  couditions  of  its  formation  will  be 
noted  below. 

l.nii.lO.  Aside  from  the  metallic  oxides  just  cited,  certain 
great  deposits  of  metallic  sulphides,  and  especially  of  chalcojty- 
I'ite  and  nickel-bearing  pyrrbotite,  are  likewise  regarded  as  the 
in'othu'ts  of  crystallization  from  fusion.     Many  Norw^egian  lo- 

'  A  (i.  Hof^boin.  Ueber  das  Noi)lieliiisyenitfjjebiet  auf  der  InselAluo. 
'-v.,/   Fihru.  For/idiKil.  XVII.,  100.214.  \X'.irK  iXencx  Julirhitcli,  1H!»(5,  I.,  2.12. 

-  W  Peterson,  (ieol,  loren.  Fmiuindl,  X\'.. 'l.V.Tl,  1H0;5.  IJ.  Sjogren, 
""'/.,  :..->,  i40-i4;j. 

'J.  H.  L.  Vofft,  Zi'itsch.  furprakt.  (Icolofjie,  Jauuarj'.  1894,  p.  ;5Sn. 

M.  II.  Pratt,  Engineering  and  ^fining  Journal  Dec.  10,  1898,  p.  696 
'^''■in)H.  Amer.  Inst.  Min.  Etig.  (issued  May,  1899). 


02 


KEMP  S  ORE  DEPOiSlTS. 


calities  and  in  America  the  Gap  Mine,  Pa. ;  the  Sudbury 
niines,  Ont.,  are  of  this  type.  The  gold-bearing  pyrrhotites  of 
Kossland,  British  Cohinibia,  resemble  it,  bnt  have  also  been 
esteemed  replacements.  All  these  sulphides  are  found  in  tin.- 
outer  portions  of  the  intrusions. 

1.00.11.  In  discussing  the  chemical  and  physical  processes 
which  have  led  to  the  production  of  the  igneous  typos  of  ore 
bodies,  it  is  important  to  emphasize  their  position  with  regard  to 
the  mass  of  the  intrusion,  i.e.,  whether  in  the  center  or  at  some 
other  point  well  within  the  intrusion,  or  whether  in  the  outer 
portions  near  tlie  contacts.  Somewhat  different  processes  may 
be  invoked  in  explanation  according  to  these  several  relations. 

1.00. 1'i.  The  titaniferous  magnetites  are  either  centrally 
jilaced  or  else  are  so  far  Avithin  the  mass  as  to  show  no  relations 
to  its  borders.  The}'  are  also  merely  exce|)tional  and  hx'al  en- 
richments of  the  magma  witb  one  of  its  more  abundant  compo- 
nent bases,  and  with  a  jiarticular  mineral,  which  is  among  the 
earliest  to  separate  in  the  process  of  crystallization,  and  which 
has  the  highest  specific  gravity  of  any  of  those  entering  into 
the  rock.  ]\I(jrozewicz'  has  sought  by  artificial  experiments  to 
determine  the  laws  which  govern  its  separation.  l)ut  he  finds 
them  complex.  The  experiments  indicated  that  mass  actinn 
plaj'ed  a  prominent  part,  and  that  with  an  al)undance  of  the  iron 
oxides  the  crystallization  of  the  magnetite  preceded  that  (if 
the  ferromagnesian  silicates;  with  less  it  began  after  them. 
The  iron  oxides  enter  as  bases  into  so  many  rock-forming  min- 
erals that  enough  to  satisfy  the  ferromagnesian  group  is  obvi- 
ously nocessar}'  before  large  amounts  of  magnetite  can  be  ex- 
pected. If,  therefore,  we  assume  a  magma  excessively  rich  in 
iron  together  with  much  magnesia,  but  low  in  lime,  alumina  and 
alkalies,  an  aggregate  of  magnetite,  olivine  and  some  })yroxene 
will  necessarily  result  on  crystallization,  as  at  Taberg  and 
Cumberland.  To  explain,  howevei",  the  central  position  of  tliis 
basic  portion  in  an  otherwise  more  acidic,  average  magma 
is  not  so  simple.  If  again  wo  assume  a  magma  fairly  rich  in 
iron,  soda,  lime,  alumina,  and  silica,  but  lacking  magnesia,  it 
is  conceivable  that  magnetite  and  labradorite  will  result  as  in 
the  anorthosites.     The  concentration  of  tlie  magnetite  seems  to 

'  .lost'f  Morozewicz.  ExperinKMitclle  l^iitfrsncluinKen  iiber  die  Kildiiug 
der  Miuerale  iin  Magma.     Tsrhcnntiks  MHIInilinKjcii,  XVIII.,  84,  18'J8. 


T|ji> 
from  ii. 
wicz.' 


L•LAt<SlFJCATIO^'  OF  OUE  DEPOSITS. 


6a 


the  writer  best  ex])laine(l  by  its  settling  in  tbe  still  molten  mass 
until  it  has  formed  considerable  aggregates.  When  once  these 
rich  aggregates  have  formed,  they  may  in  the  process  of  erup- 
tion or  intrusion  take  almost  any  place  iu  the  resulting  rock.' 
Physico-chemical  reactions  may,  however,  be  opeiative  of 
which  at  jiresent  we  are  not  aware.  Vogt"  has  suggested 
that  w^ien  magnetite  crystals  have  formed  in  the  still  molten 
iiuigma  they  ma}'  become  aggregated  by  their  magnetic  attrac- 
tions, but  the  mineral  loses  its  magnetism  even  at  a  temjier- 
atnre  below  redness,  and  it  is  doidjtful  if  this  property  could 
att'ect  the  result. 

l.Oi;.  i;i.  Chromite  appears  at  times  in  masses  well  within 
the  peridotite  or  serpentine  which  contains  it,  and  it  also  is  no- 
ticc'iibly  abundant  near  the  contact''  in  other  occurrences. 
Corundum  furnishes  a  close  jiarallel.  It  has  been  met  in  very 
great  (juantity  in  Ontario,'  north  of  Lake  Ontario,  in  nephe- 
lini'-syeuite,  favoring  certain  varieties  of  the  rock,  but  dis- 
tril)uted  all  through  it.  In  North  Carolina''  it  favors  the  outer 
portions  of  the  peridotite  ((Uniite)  in  which  it  is  found.  Sap- 
phires of  gem  (juality  have  been  foimd  in  Montana  in  a  basic 
(like  consisting  chiefly  of  biotite,  diopside  and  magnetite.  Some 
secondary  products  from  unrecognizable  originals  are  also 
present." 

The  chemical  conditions  under  which  corundum  separates 
from  igneous  magmas  have  been  verj'  clearly  shown  b}'  Moroze- 
wiez. '     Without  regard  to  the  percentage  of  silica  in  the  rock, 


'I  F.  Kiin|).  "  The  Titaniferoiis  Jragnetites  of  the  Adirondacks,"  etc., 
.\7A'.  Attn.  liCj).  Dir.  f.  ,S.  GcoJ.  Snrrri/  (in  jjvpks). 

'•' Diouielsc  iif  JeriJinahiit'orekoiiister.  Kiistiaiiia.  1892,  Resume  in  Ger- 
man, p.  l-l.'^i.  Vogt  also  nieutioTis  the  <'oneeutvation  by  settling  which  is 
set  fortli  above. 

' .).  II.  Priitt.  "Tlie  OccurreiH'e,  Orifjjin  and  Clieniical  Composition  of 
Clu-oiuite"  (ah.stract).  Eiif/hiccriinj  tind  Mining  Journal.  Dec.  1(t.  isils,  ]). 
'inii.  'J'nina.  Atticr.  Jnsf.  Min.  Eikj..  February,  ISKft,  New  York  meeting. 
Refers  t'sjHH'ially  to  North  Carolina. 

'  W.  (i.  Miller,  Report  of  the  Ontario  Bureau  of  Klines,  VII.,  207,  1S98. 

'  ■!  II.  Pratt.  '•C)n  tlie  Origin  of  the  Corundum  .Associated  with  the 
Peiiddiiies  in  North  Caiolina."  Aiiifi:  Jonr.  Sci..  ,;idy,  lHi)H.  }>.  4!>. 

*  L.  V.  Pirsson,  "Corundum-hearing  Rock  from  Yogo  Gulch,  Mootaua," 
Amcr.  Join:  Sci..  December,  IS'tT,  p.  421. 

•lo/if  Morozcwicz.  E.\])erinientelle  Untersuchungen  uber  die  Rildung 
tier  Miiiurale  im  Magma,  7\'<Iicr)n(tl.-s  MUtiniliinifci:,  XVIII.,  80,  1898. 


64 


KEMP'S  ORE  DEPOSITS. 


greater  than  1.     In  this  case  spinel  may 


provided  that  it  lies  within  the  limits  mot  in  natural  magmas, 
free  alumina  will  separate  as  corundmn,  when  the  nKjlecular 
ratio  of  the  ahuniua  to  the  other  bases  is  greater  than  unity, 

A],(), 
*•  ^•'  R/)+R()H-K,()3 
be  anticipated  as  an  associate.  When,  therefore,  corundum 
is  found  in  a  natural  igneous  rock  this  condition  must  have 
been  met  at  the  time  it  crystallized.  As  to  the  causes  whicli 
have  produced  the  concentration  at  the  borders,  the  dis- 
cussion is  the  same  as  that  given  luider  the  next  topic. 

!.()(!.  14.  The  deposits  of  nickeliferous  and  auriferous  pyr- 
rhotite  and  of  chalcopyrite,  which  are  found  in  the  rims  of 
basic  intrusions,  present,  so  far  as  mining  is  concerned,  nuich 
larger  developments  than  the  chromite  and  corundum  just  re- 
ferred to,  and  the  important  a])})lications  of  nickel  in  armor- 
plate  have  led  to  caret  id  study  of  tlie  ores.  They  are  recognized 
by  most  observers  as  crystallizations  from  fusion, and  the  prol)- 
lem  arises  as  to  the  causes  which  have  brought  them  into  their 
present  position. 

Tliat  individual  intrusions  vary  from  a  more  acidic  (or  sili- 
ceous) composition  at  tlie  center  to  a  more  basic  one  at  the  bor- 
ders is  well  established  by  observation  and  by  progressive 
analyses  in  a  munber  of  instances.' 

An  explanation  of  these  relations  has  been  sought  in  what  is 
known  as  Soret's  principle.^  It  was  i)roved  by  experiments  in 
1879  by  Soret,  a  French  chemist,  that  if  differences  of  tempera- 
ture are  induced  in  a  solution  of  conmion  salt  or  other  sub- 
stance in  water,  the  dissolved  material  will  become  relatively 
concentrated  in  those  portions  in  which  the  temperature  is  low- 
est. It  has  also  been  shown  that  this  would  f()lU)\v  from  tlie 
laws  of  osmosis,  and  that  the  relative  degrees  of  concentration 


'  See  Lawson  and  Shutt,  on  a  diabase  dike  in  tlie  Rainy  Lake  Region. 
Proc.  Amer.  Assoc.  Adw  Sci.,  IHSD,  24(>;  Alfred  Itarker  on  an  Englisli 
gabbro.  Qiifn'trrli/  .Toiirnal  of  the  (U'olorjiral  Soriifi/,  ]S!»4,  3'2(};  W.  S. 
Bayley  on  Minnesota  gabbros,  .louriKil  of  (i'coId;/!/.  III.,  824,  18!>5. 

'  The  bearing  of  thisex})lanation  of  niagniatic  differentiations  in  igneous 
rocks  niton  tbese  nickeliferons  de]«)sits  bns  been  es|H'('ially  set  fortb  liy 
J.  H.  L.  Vogt  <tt'  Kristiaiii.'.  Norway,  in  tlie  Zcif.'tcliriff  fitr  ProkthiJn' 
Geologic.  I.,  125,  181);{.  iiiuicr  tlie  title  "Sulphidisehe  Ansseheidungeu  vdii 
Niekel-snli>bid-erzen,"  etc. .  Utiier  related  papers  a]>]icMr  in  the  same,  I.  1 
and  257;  II.  -il,  1:54  and  IT;!. 


\vouI( 

(/.''., 

jiciatii 

ill     SIK 

inagni 
J  (hides 

\VC  I't'g 

{U'ocess; 
tlicse  w 
cooled, 
(laiit  af 
tliat  av 
The  mi 
under  1 
and  st'vi 
lu   til 
especial 
ritic  iiit 
Vogt,  ci 
tremely 
fully  set 
several 
away  fr(| 
Oap.Mii 
sition. 
tions  \\\ 
'"^orot's  pj 
same    asl 
i'yrrliotif 
cobalt  ri 
peutlaudi 
C'lialcop\ 
tity.     v', 
tive  aiiiol 
•"'J'ecially 

'  S.  L.  P,. 
June,  ls!);)| 
nou-ininrne] 
'■(''K'lie.s  at ; 
is(NiFci,s. 


^F 


CLASSIFICATION  OF  OUK  DEPOSITS. 


65 


would  lie  to  one  another  inversely  as  the  ahsoliite  teniperaturea 
(/.^'.,  teniiK'rature  Centigrade  plus  Ti'-)).  The  lower  the  tem- 
prriiture,  therefore,  the  more  dissolved  material  would  collect 
ill  such  chilled  portion.  If  nov/  we  consider  a  fused  rock 
iMMfinia  as  a  complex  solution  of  several  silicates,  oxides,  sul- 
jiliidcs  and  one  or  two  rarer  compounds,  some  in  others,  and  if 
we  regard  as  the  least  soluble  those  that  crystallize  first  in  the 
process  of  cooling,  we  are  led  by  Soret's  principle  to  infer  thfit 
tliese  would  tend  to  become  concentrated  in  the  jiortions  first 
oooled,  and  that  in  such  portions  they  would  be  especially  abuu- 
(laiit  after  consolidation.  The  portions  of  an  igneous  intrusion 
tliat  are  first  cooled  are  obviously  those  next  the  wall  rock. 
The  minerals  which  crystallize  first  are,  as  set  forth  earlier 
under  1.0:5.0.5,  magnetite,  ilmenite,  apatite,  pyrite,  pyrrhotito, 
and  several  minor  ones. 

In  the  case  of  nickel iferous  pyrrhotite  the  ore  bodies  are 
especially  rich  along  or  near  the  contacts  of  gabbroic  and  dio- 
ritic  intrusions  with  their  walls,  and  the  paper  of  J.  H.  L. 
Vogt,  cited  in  the  footnote,  has  served  to  bring  out  some  ex- 
tremely interesting  facts.  The  geological  relations  are  more 
fully  set  forth  later  on  under  nickel  and  in  connection  with 
several  American  occurrences,  but  it  may  be  here  added  that 
away  from  the  outer  wall  the  ore  bodies  fade  (at  least  at  the 
Gap  Mine,  Pa.)  into  barren  gabbro,  by  a  fairly  gradual  tran- 
sition. In  these  respects  they  conform  cjuite  closel}-  to  condi- 
tions which  would  result  from  a  development  according  to 
Sorot's  principle.  We  also  find  in  such  ore  bodies  much  the 
same  association  of  minerals,  wherever  they  are  mined. 
Pyrrhotite  is  in  greatest  amount  and  contains  the  nickel  and 
cobalt  rejilacing  a  portion  of  its  iron :  as  the  rarer  mineral 
pentlaudite,'  or  as  secondary  coatings  of  millerite  in  cracks. 
Chalco})yrite  is  invariable'  present,  often  in  im])ortant  (juan- 
tit}'.  V  ogt  has  sought  to  trace  out  some  constancy  in  the  rela- 
tive amounts  of  these  several  metals,  but  the  attempt  is  not 
specially  successful.     He  also  cites  in  connecti  on  with  a  dis- 


'  S.  L.  IVnfieUl,  PeutlanditefromSudliuiy,  Out.,"  etc.,  Amer.  Jour.  Sei., 
June,  IM!);^,  41)3.  Peutlaiulite  is  u  .suli)lii(le  of  iron  iiiul  niekel,  isometric, 
nuu-iii!it,'netie,  ami  with  a  somewhat  varying  jjerceiitage  of  niekel.  wliicli 
reaches  at  Sudbury  34. '.J;!     The  general  formuhi  from  Peutield's  analysis 

is  (NiFe)S. 


ou 


KKMl'S  OHK  DKJ-OHITH. 


cussion  of  tlieir  early  formation  and  ooniLination  witli  sulplmi' 
in  tlio  fused  niaj^nia,  tlio  laws  which  wo  know  apj)!}'  in  tin' 
nietallurgioal  processes  involving  slags  and  mattes.' 

1.06.15.  Admitting  that  the  bases  iron,  nickel  and  copper, 
along  with  others,  have  been  concentrated,  while  etill  in  tln' 
state  of  ions,'' at  the  borders  by  Soret's  principle,  or  by  8onit> 
otlmr  process,  perhaps  not  clearly  understood,  objection  Iwis 
still  been  mad(^  to  the  igneous  origin  of  suliibides,  because  it  is 
believed  that  the  conditions  in  a  fused  magma  are  oxidizing — 
as  witness  the  presence  of  the  several  metals  in  almost  all 
igneous  rocks  as  oxides — and  because  oxidizing  conditions  would 
be  inimical  to  the  production  of  sulphides.  When  sid])hi(l('s 
form  in  a  furiiace,  it  is  \jrged  that  the  fuel  creates  a  reducing,' 
action,  and  that,  otherwise,  sulphitiesAvould  be  imjKtssible.  '^I'lio 
analogy  of  a  furnace  is  not  to  be  too  shaiply  urged  in  objection. 
for  the  reason  that  no  blast  of  oxygen  is  blown  through  a 
magma,  so  as  to  create  of  itself  an  intense  oxidation.  The 
abundance,  moreover,  of  ferrous  oxitle  in  basic  rocks  indicates 
that  the  oxidizing  conditions  are  not  marked.  Nevertheless, 
to  meet  the  objectious  to  the  formation  of  sul})hides  in  niaK- 
mas,  while  assuming  the  greater  basicity  of  the  outer  ])ortionsiif 
the  mass,  the  writer'  has  suggested  that  the  escape  of  sulphur- 
ous gases  through  the  still  molten  rock  along  the  contacts 
woidd  produce  sulphides  of  metals  already  there,  even  though 
the  genei'al  conditions  in  the  magma  were  oxidizing.  In  the 
original  paper  the  reactions  involved  are  justilied  on  the  basis 


*  As  is  well  known  the  connnon  metals  niny  be  ran,t;;e(l  in  the  following 
order  ("  Fournet's  Series  " )  uccortliug  to  tlieir  decreasiiit^  atliuity  for  sul- 
phur, Cu,  Ni,  Co,  Fe,  Sn,  Zn,  Pb,  Ak,  Sb,  As,  see  Voj:;t,  Zcilsclt.  fiir  jiralt. 
Geologic,  I.  268.  In  their  bearings  on  geological  ])heiion»eua  the.se  niftal- 
lurgical  laws  were  ilisenssiMl  many  years  ago  by  Leoiihard  in  Hi'iitcin  i- 
zciKjtiixsc  unci  (indcre  mif  Kihistiichi  iti  W'lye  (jrhildilv  Mini  ndicii  (ih 
Stilzpnnkte  geolorfishcr  Hjipotlum'n,  Stuttgart,  1H.")H.  The  sncoesisioii  is 
determimnl  by  the  laws  of  thermochemistry,  and  necessarily  tl.e  sulphiilt's 
will  fonn  in  order  according  to  the  amounts  of  heat  developed  by  the 
reaction,  from  the  greatest  to  the  lea.st. 

"  The  term  ion  is  employed  in  modern  chemistry  to  describe  those  ]iar 
tial  molecules  that  are  held  iu  an  incomplete  .state  by  electrical  force. 
The  word  is  derived  from  the  Greek  for  "going"  or  "moving,"  and  was 
suggested  by  the  partial  molecules  that  are  in  transit  in  an  electro]ilatiiifi 
bath. 

'  J.  F.  Kemp,  The  Mineral  Industry  for  ls!(.-,,  Vol.  IV.,  7C1-7(U5. 


mtf 


CLASSIFICATIOS  <tl'  (HIE  DF.I'nsiTH. 


07 


of  ii]i3'sical  oheniistry,  and  tlu^  proccHS  conceived  is  analogous 
to  lu'ssemerizing  a  bath  of  oxides  with  8nlj)hur  vapor,  as  con- 
trasted witli  tlio  nsnal  artificial  process  of  oxidizing  a  bath  of 
molten  Hidiihidos  with  a  blast  of  air. 

(J,  F,  Becker' has  presented  a  strong  argument  against  the 
ability  of  Soret's  j)rinciple  to  accomplish  serious  results  in  ef- 
fecting a  (litl'erentiation  of  an  origin;  :ly  homogeneous  lluid 
niagnui  into  others  of  different  compositions,  and  cites  in  sup- 
jiort  of  his  argument  the  slowness  and  feebleness  of  molecular 
tlow  and  diffusion  as  indicated  by  artificial  experiments  with 
siiliiblo  salts.  The  viscosity  of  fused  rock  gives  additional 
force  to  the  objection.  He  therefore  attributes'"  the  changes  to 
convection  currents,  which  would  bo  inevitably  set  up  in  the 
mass  by  its  differences  of  temperature  and  which,  as  they 
passed  along  the  cold  surfaces  inclosing  the  molten  fluid,  would 
coat  them  with  the  earlier  and  less  mobile  cr^ystallizatious.'' 
This  process  of  "fractional  crystallization"  is  bej-ond  question 
a  most  important  sjiggestion,  and  it  may  obviate  some  of  the 
difficulties  that  have  hitherto  been  serious. 

l.oii.Ki.  As  opposed  to  the  igneous  view  others  have  re- 
garded ores  of  this  type  as  contact  deposits,  brought  about  by 
solutions  circulating  along  the  outer  portions  of  the  intrusions, 
and  replacing  or  im|)regnating  the  gabbro,  more  or  less,  witli 
ore.  The  conception  is  a  time-honored  one:  it  involves  nothing 
unreasonable,  and  has  the  sujtport  of  some  of  our  ablest  inves- 
tigators, as  Emmons'  and  Posepnj','^  but  the  objections  to  the 
igneous  conception,  it  is  fair  to  state,  were  not  based  on  obser- 
vations of  the  phenomena,  but  on  general  theoretical  considera- 
tions. 

'  G.  F.  Beckor,  "Some  Queries  on  Rock  Differentiation,"  Amcr.  Jour. 
ScL,  Jrmuary,  lsfl7,  31. 

'  (i.  F.  Becker,  "Fractional  Crystallization  in  Hocks,"  Idem,  October, 
18!I7,  2r)7. 

'  A  vory  siigfjostive  pnper  in  this  cotinection  and  one  tliat  lias  inijiortant 
applications  to  tlie  SiKll)\iry,  (^nt.,  ores,  is  tlie  follovviiij;:  "Segregation  in 
Ores  ami  Matte.s,"  by  David  H.  Browne,  School  of  Mines  Quarterly,  July, 
IHiio,  2!I7-:!U. 

^  !^.  F.  Emmons,  "Geological  Distrilmtion.of  tlie  Useful  Metals  in  the 
United  States,"  Trans.  Amer.  Inst.  Min.  Eng.,  Chicago,  1893.  Reprint 
pp.  If^l'l. 

'  F.  \)sepny,  "The  Genesis  of  Ore  Deposits,"  Jrfcm.     Reprint  p.  194. 


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68 


KEMP'S  ORE  DEPOSITS. 


1.00. 17.  Under  II.  1,  the  precipitating  agencies  are  men- 
tioned, which  are  the  chief  causes  in  the  chemical  reactions  of 
deposition,  and  these  run  through  all  the  subterranean  cavities 
as  well.  Their  general  application  is  esteemed  self-evident.  The 
large  part  plaj'ed  by  organic  matter,  both  when  living  and 
when  dead  and  decaying,  is  notable.  Its  office,  even  in  precipi- 
tating the  gangue  minerals  in  surface  reactions,  we  are  just  be- 
ginning to  appreciate.  Siliceous  sinters  have  been  shown  by 
W.  H.  Weed  to  be  formed  in  the  hot  springs  of  the  Yel- 
lowstone Park  through  the  agency  of  algte,  and  A.  Eothpletz 
has  recently  proved  that  the  calcareous  oolites  around  the 
Great  Salt  Lake  are  referable  to  minute  organisms.  Many 
accumulations  of  iron  ores  have,  with  reason,  been  attributed 
to  the  same  agency ;  but  for  this  metal  ordinary  and  common 
chemical  reactions  are  oftenest  applicable.  When  organic  mat- 
ter decays,  sulphurous  gases  are  one  of  the  commonest  products, 
and  likewise  one  of  the  most  vigorous  of  precipitants.  Thus, 
under  Example  24,  Paragraph  2.0(i.03,  when  speaking  of  the 
Wisconsin  zinc  and  lead  mines,  it  will  be  seen  that  such  au 
agency  from  decaying  seaweeds  has  been  cited  by  both  Whit- 
ney and  Chamberlin.  When  the  products  of  this  decomposi- 
tion become  imprisoned  in  the  rocks  as  oils  and  gases,  their  ac- 
tion i.  unmistakably  important  and  is  especially  available  ir. 
limestones.  Organic  matter  is  a  powerful  reducing  agent  as 
well,  and  in  this  way  is  capable  of  bringing  down  metallic 
compounds.  The  silver-bearing  sandstones  of  southern  Utah 
are  cases  in  point,  as  they  afford  plant  impressions  now  coated 
with  argentite.  The  purely  physical  agencies  cited  under  (</ ) 
have  also  an  important  role. 

1.00, 18.     Under    2(rt)  the   uprising  solutions    may    be    di- 
verted by  porous  strata,  so  as  to  pass  through  them,  and   be 
subjected  to  precipitating  agents  of  one  kind  or  another.    Porous 
beds  furnish  the  simi)lest  kiiul  of  cavities,  and  starting  with  these 
the  scheme  is  developed  in  a  crescendo  to  the  most  complicated 
The  purely  chemical  action  of  limestone  beds,  however,  seems 
at  times  to  oome  into  play  and  to  oause  precipitation  along 
them.     Of  all  rocks  they  are  the  most  active  chemical  reagent. 
It  may  be  questioned  with  reason  as  to  whether  caves  or  cav- 
erns (4),  properly  so  called,  have  formed  a   resting-place    for 
ores  as  often  as  some  observers   have   supposed.      So    many 


II 


CLASSIFICATION  OF  ORE  DEPOSITS. 


69 


which  have  beeu  cited  as  such  may  with  greater  reason  be 
referred  to  shrunken  replacements  that  each  case  should  be 
clearly  proven. 

1,00.19.  Undet  (5)  brecciated  beds,  whose  fragments  are 
coated  and  whose  interstices  are  filled  with  ore,  are,  with  great 
reason,  referred  to  the  collapse  from  the  removal  of  a  support- 
ing layer.  In  addition  to  the  illustration  cited, the  red  hematite 
deposits  of  Dade  and  Crawford  counties,  Missouri,  have  been 
thought  to  have  had  a  similar  origin.  Such  phenomena  are 
only  to  be  expected  in  regions  that  have  long  been  land. 
Cracks  at  the  bends  of  folds  may  have  occasioned,  in  cases, 
ini})regnations  and  disseminations,  even  when  their  character 
is  obscured.  The  cracks  need  be  but  small  and  numerous  to 
have  produced  far-reaching  results.  If  a  fault  fissure,  as  a 
possible  conduit  of  supply,  crosses  the  axis  of  the  fold,  the  nec- 
essary conditions  are  afforded  for  extended  horizontal  enrich- 
ment. Recent  explorations  with  the  diamond  drill  at  Mine  la 
Motte  seem  to  corroborate  such  an  hypothesis.  Should  the 
anticline  or  roll  afterward  sink  toward  the  horizontal,  a  verj' 
puzzling  deposit  might  originate.  Shear  zones  have  been  al- 
ready discussed  at  length  (1.02.03),  as  have  true  veins  and 
volcanic  necks  (see  also  2.00.;20).  As  regards  contact  deposits, 
tlie  igneous  rock,  which  usually  forms  one  wall,  may  serve  two 
different  purposes.  It  may  act  merely  as  an  impervious  bar- 
rier which  directs  solutions  along  its  course,  or  serves  to  hold 
them,  either  because  it  is  itself  bent  into  a  basin-like  fold,  or 
because  it  forms  a  trough  with  a  dense  bed  dipping  in  an  o})- 
posite  direction.  Such  relations  occur  in  the  Marquette  and 
Gogebic  ranges  of  the  Lake  Superior  iron  i-egion.  It  is  not 
apparent  that  in  these  cases  the  heat  of  the  igneous  I'ock  has  in 
auy  degree  stimulated  circulations.  In  tlie  more  characteristic 
"contact  deposits"  the  igneous  rock  has  a[)parently  been  a  strong 
promoter  of  ore-bearing  solutions,  and  has  often  been  the  source 
of  the  metals  tliemselves.  This  form  of  dei)0sit  becomes,  then, 
an  attendant  phenomenon,  or  even  a  variety,  of  coniiict  meta- 
morjihism. 

The  classic  illustration  of  it  is  furnished  by  the  deposits  of 
tin  ore  which  have  been  especially  developed  along  the  con- 
tacts of  granite  intrusions.  Granite,  as  is  well-known,  is  the 
most  potent  of  all  rocks  in  bringing  about  contact  metamor- 


70 


KEMP'S  ORE  DEPOSITS. 


i 
J 


phism.  It  seems  to  be  especially  rich  in  mineralizers,  and  as  its 
great,  intruded,  batholitic  masses  slowly  crystallize,  they  emit 
boracic,  hydrofluoric  and  other  vapors  in  exceptional  volume. 
Wall  rocks  are  greatly  corroded  and  charged  with  tourmaline, 
fluorite,  axinite,  topaz,  fluoric  micas  and  cassiterite.  Peg- 
matite dikes  or  veins  are  sent  off  as  apophyses,  and  are  charged 
with  the  same  association  of  minerals.  If  the  walls  are  them- 
selves granitic  in  composition,  the  feldspar  becomes  greatly 
corroded,  and  may  be  replaced  by  quartz  and  fluoric  micas  with 
more  or  less  cassiterite.  Pegmatites  consisting  essentially  of 
the  same  minerals  are  also  produced,  and  both  varieties  are 
called  g'-eisen,  and  are  recognized  as  the  characteristic  gangue 
of  tin  ores  the  world  over.  The  clue  to  the  formation  of  the 
cassiterite  in  these  surroundings  was  furnished  by  the  early 
experiments  of  Daubree,^  who  volatilized  the  bichloride  of  tin 
and  brought  it  into  contact  with  steam  in  a  tube,  obtaining  by 
double  decomposition  crystals  of  oxide  of  tin,  identical  in 
form  with  the  natural  ones.  In  Nature,  however,  the  fluoride 
■)f  tin  is  the  more  probable  source.  The  processes  by  which 
minerals  and  ores  are  emitted  from  igneous  rocks,  in  the  form 
of  heated  vapors,  are  often  called  pneumatolitic;  and  if  water 
also  plays  a  part,  pneumato-hj'datogenic. 

Under  11  chromite  is  the  chief  illustration.  The  mineral  is 
practically  limited  to  serpentinous  rocks,  and  is  distributed 
through  them  in  irregular  masses.  It  has  been  considered  to  be 
a  product  of  alteration. 

l.OO.^O.  III.  The  debris  that  results  from  the  weathering 
of  rock  masses  under  the  action  of  frost,  wind,  rain,  heat  and 
cold,  is  washed  along  by  the  drainage  system  of  a  district,  and 
the  well-known  sorting  action  transpires,  which  is  so  impor- 
tant in  connection  with  the  formation  of  the  sedimentary  rocks. 
Minerals  of  great  specific  gravity  tend  to  concentrate  by  them- 
selves, while  lighter  materials  are  washed  farther  from  tbe 
starting  point,  and  settle  only  in  still  water.  Stream  bottoms 
supply  the  most  favorable  situations,  and  in  their  bars  are 
found  accumulations  of  the  heavier  minerals  which  are  in 
the  surrounding  rocks.  The  commonest  of  these  are  magnetite, 
garnet,  ilmenite,  wolframite,  zircon,  topaz,  spinel,  etc.,  and  with 
these,  in  some  regions,  native  gold,  platinum,  iridosmine.  etc.; 

'  Annules  des  Mines,  XVI.,  129. 


CLASSIFICATION  OF  OliF  DEPOSITS. 


n 


ill  other  places  cassiterite,  or  stream  tin,  as  described  under  tin. 
Even  an  extremely  rare  mineral,  such  as  monazite,  may  make  a 
sandbar  of  considerable  size.'  The  action  of  the  surf  or  smaller 
sluire  waves  is  also  a  favorable  agent.  The  throw  of  the 
breaker  tends  to  cast  the  heavier  material  on  the  beach,  where 
its  <^reater  specific  gravity  may  liold  it  stationary.  The  heav- 
ier minerals  may  be  sorted  out  of  a  great  amount  of  beach 
saiul.  Magnetite  sands,  which  have  accunmlated  in  this  way, 
are  of  quite  wide  distribution,  and  at  present  are  of  some 
though  not  great  importance.  (Example  15.)  With  the  mag- 
netite are  found  grains  of  garnet,  hornblende,  augite,  etc.,  and 
often  ilmenite.  Gold  is  concentrated  in  the  same  way  along 
the  Pacific  by  the  wash  of  surf  against  gravel  cliffs.  In  aban- 
doned beaches  of  Lake  Bonneville,  near  Fish  Springs,  Tooele 
County,  Utah,  placers  of  rolled  bowlders  of  argentiferous  ga- 
lena have  been  worked. 

A  superficial  deposit  of  somewhat  different  origin  is  the  bed 
of  lieniatite  fragments  that  mantles  the  flanks  of  Iron  Moun- 
tain. Missouri,  and  runs  underneath  the  Cambro-Silurian  sand- 
stones and  limestones.  This  seems  to  have  been  produced  h\ 
the  subaerial  decay  of  the  porphyry  which  formerly  inclosed 
the  ore.  The  heavier  specular  ore  has  thus  been  concentrated 
by  its  greater  specific  gravity  and  resistant  powers.^ 

l.OO.'^l.  Tliere  remaiii  a  few  of  great  importance,  but 
whose  geological  history  is  less  clearly  understood.  They  are 
nearl}'  all  involved  in  processes  of  regional  metamorphism,  and 
therefore  in  some  of  the  most  difficult  problems  of  the  science. 
Lenticular  beds  or  veins  of  magnetite  and  pyrite  that  are  inter- 
bedded  with  schists,  slates,  or  gneisses  are  the  principal  group. 
Such  magnetite  bodies  have  been  regarded  as  intruded  dikes, 
iis  t)rigiii{)l  bodies  of  bog  ore  in  sediments,  which  have  later  be- 
ciiine  metamorphosed  ;  and  as  concentrated  delta,  river,  or  beach 
niiii^netite  sands.  It  is  possible  that  in  instances  they  may  be 
replaced  bodies  of  limestone,  afterward  metamorphosed.  The 
lenticular  sliape  and  the  frequent  overlapping  arrangement  of 
tlie  feathering  edges  in  the  foot  wall  are  striking  phenomena. 

The  overlap  was  referred  by  H.   S.  Munroe,   in  the  School 

'  Set- O.  A.  Derby,  Aiiirr.  Jour.  Set.,  III.,  xxxvii.,  p.  108. 
■  S(H' R.  Punipeby,  "Tlie  Secular  Disiutegration  of  Hocks,"  Proc.  Geol. 
Soc.  Amcr.,  Vol.  II.,  December,  1890. 


II 

'     1  ' 

I  Hi 


i 

\    \  ■ 

HI  '    ' 

72 


KEMP'S  ORE  DEPOSITS. 


of  Mines  Quarterly,  Vol.  III.,  p.  34,  to  stream  actiou  during 
mechanical  deposition,  and  a  figure  of  some  hematite  lenses  in 
the  Marquette  region  was  given  in  illustration.  The  arrange- 
ment in  instances  also  suggests  the  shearing  and  huckling  pro- 
cesses of  dynamic  metamorphism  and  disturbance.  The  individ  ■ 
ual  lenses,  now  in  linear  series,  were  thus  all  one  original  bed. 
The  crumpling  of  the  schistose  rcxjks  has  pinched  them  by 
small  buckling  folds  and  shoved  the  ends  slightly  past  each 
other  in  the  process  so  familiar  in  the  production  of  reversed 
faults  from  monoclines.  Sheared  granitic  veins  on  a  small 
scale  are  a  not  uncommon  thing  in  areas  of  schistose  rocks, 
such  as  Manhattan  Island,  in  the  city  limits  of  New  York,  and 
suggest  strongly  this  explanation.  Should  the  compression  not 
go  so  far  as  to  bring  rupture  of  the  bed,  but  onlj'  a  thickening 
by  the  formation  of  a  sigmoid  fold,  it  would  occasion  an  en- 
larged cross  section,  as  has  been  suggested  by  B.  T.  Putnam' 
for  the  great  magnetite  ore  body  at  Mine  21,  Mineville,  in  the 
Lake  Champlain  region. 

1.06.22.  Quartz  veins,  often  auriferous  and  of  a  lenticular 
character,  furnish  another  puzzling  ore  body.  They  are  com- 
monly called  segregated  veins,  and  lie  interfoliated  in  slates  or 
schistose  rocks.  If  in  a  pre-existing  cavity,  the  cavity  must 
have  been  formed,  either  by  the  opening  of  beds  under  compres- 
sion, or  by  displacement  along  the  bedding,  so  that  depressions 
came  opposite  each  other  Replaced  lenses  of  limestone  which 
had  been  squeezed  into  this  shape  froju  an  original, connected  bed 
should  also  be  instanced  as  a  possibility.  But  notwithstanding,' 
the  time-honored  nature  of  the  conception  of  these  "segregated" 
veins,  there  is  little  doubt  that  they  are  practically  all  mere 
varieties  of  fissure  veins,  which  have  been  pinched  into  the 
separated  lenses  by  pressure. 

1.06.23.  The  veins  that  contain  cassiterite  in  many  parts  of 
the  world,  and  that  yet  have  the  mineralogical  composition  of 
granite,  are  another  product  of  metamorphic  actiiju,  both  con- 
tact and  regional.  The  gangue  minerals,  feldspar,  q  art z, 
and  mica,  are  quite  characteristic  of  acid,  igneous  r(x?k.3,  buv 
the  coarseness  of  the  crystallization  in  the  comparatively  nar- 
row veins  bars  out  a  normal  igneous  form  of  origin.  All  our 
artificial  methods  of  reproducing  these  minerals  lead  us  to 
'  '  Tenth  t'ensus,  Vol.  XV..  110. 


CLASSIFICATION  OF  ORE  DEPOSITS. 


73 


infer  that  the  veins  were  filled  at  a  high  temperature  and  pres- 
sure, therefore  at  considerable  depths,  and  through  the  aid  of 
steam.  Cassiterite  has  also  been  detected  in  a  few  rare  cases, 
under  such  circumstances  that  it  seemed  to  be  an  original  min- 
eral in  igneous  granite.  It  is  probable,  therefore,  that  it  may 
in  instances  be  an  original  and  early  crystallization  from  an 
igneous  magma,  much  as  is  magnetite.  More  observed  cases 
would  be  welcome  as  evidence. 

1.06.24.  Fahl bands  should  be  mentioned  here.  The  term 
refers  to  belts  of  schists,  which  are  impregnated  with  sulphides, 
but  not  in  sufficient  amount  in  the  locality  Avhere  the  name  was 
tirst  applied  (Kcingsberg,  Norway)  to  be  available  for  ores. 
The  decomposition  of  the  sidphides  gave  the  schists  a  rusty  or 
rotten  appearance  that  suggested  the  name.  Whether  the  ores 
are  an  introduction  into  the  schist,  subsequent  to  metamorphism, 
or  a  deposit  in  and  with  the  original  sediment,  is  a  doubtful 
point.  The  practical  importance  of  these  fahlbands  lies  in  the 
enriching  influence  that  they  exert  on  the  small  fissure  veins 
that  cross  them. 

1.0l!.25.  The  phraseology  of  the  above  schemes  will  be  em- 
ployed in  the  subsequent  descriptions.  In  addition,  much  em- 
})hasis  will  be  placed  on  the  character  of  the  rocks  containing 
the  deposits,  whether  unaltered  sedimentary,  igneous,  or  meta- 
morphic.  and  whether  in  the  first  and  last  cases  igneous  rocks 
are  near,  for  these  considerations  enter  most  largely  into  ques- 
tions of  origin.  The  ore  deposits  are  illustrated  by  examples, 
somewhat  as  has  been  done  by  one  of  the  best  of  modern  writers 
abroad.  Von  Groddeck.  The  word  "example"  is  preferred  to 
"type."  which  was  employed  by  Von  Groddeck,  because  it  im- 
plies less  of  an  individual  character.  We  may  cite  deposits 
under  difllerent  metals  thus  which  all  might  belong  to  one  type. 
Under  each  metal  will  be  given,  first,  a  list  of  general  treatises 
and  papers.  These  will  be  marked  "Hist."  when  especially 
valuable  as  history,  and  "Rec."  when  recommended  for  ordi- 
nin-y  examination.  If  not  marked  by  either,  they  are  more 
adapted  for  special  investigations. 


I '% 


u 


KEMP'8  ORE  DEPOSITa. 


hi.: 


GENERAL  REFERENCES  ON  ORE  DEPOSITS. 

Adams,  F.  D.  "On  the  Igneous  Origin  of  Certain  Ore  Depos- 
its," Oeneral  Mining  Association  of  the  Province  of 
Quebec,  January,  181)4. 

Ansted,  D,  T.  "On  Some  Eemarkable  Quartz  Veins,"  Qmir. 
Jour.  Geol.  Sci.,  XIII.,  '^4(J. 

Barus,  Carl.  "The  Electrical  Activity  of  Ore  Bodies,"  Travis. 
Amer.  Inst.  Min.  Eng.,  XIII.,  417.  (See  also  Becker's 
Ponograph  on  the  Coinstock  Lode,  p.  310,  for  refer- 
ences to  other  papers. ) 

Becker,  G.  F.  "The  Relations  of  the  Mineral  Belts  of  the  Pa- 
cific Slope  to  the  Great  Upheavals,"  Amer.  Jour.  Sci., 
III.,  28,  209,   1884. 

Belt,  Th.  "Mineral  Veins;  an  Inquiry  into  their  Origin, 
founded  on  a  Study  of  the  Auriferous  Quartz  Veins  of 
Australia,"  London,  18G1. 

Bischof,  G.  "On  the  Origin  of  Quartz  and  Metalliferous 
Veins,"  Jameson^ s  Journal,  April,  1845,  p.  344.  Ab- 
stract, Amer.  Jour.  Sci.,  I.,  49,  396.  Advocates  aque- 
ous deposition. 

Brown,  A.  J.  "Formation  of  Fissures  and  the  Origin  of  their 
Mineral  Contents,"  Trans.  Amer.  Inst.  Min.  Eng.,  II.. 
215. 

Bulkley,  F.  G.  "The  Separation  of  Strata  in  Folding,"  Idem, 
XIII,  384. 

Campbell,  A.  C.  "Ore  Deposits,"  Engineering  and  Mini)ig 
Journal,  July  17,  1880,  p.  39. 

Cotta- Prime  von.  "Ore  Deposits."  German,  by  Von  Cotta. 
1859;    English  translation  by  Prime,  1870.     Rec. 

Crosby,  W.  O.  "A  Classitication  of  Economic  Geological  De- 
posits based  on  Origin  and  Original  Structure,"  Amer. 
Geologist,  April,  1894,  p.  249.     Rec. 

Cumenge,  E.,  et  Robellaz,  F.  L'Or  dans  la  Nature.  Paris, 
1898.     (Being  issued  in  parts,   1899.) 

Daubree.  G.  A.  Etudes  syuthetiques  de  Geologic  experimentale 
Paris,  1879. 


It 


CLASSIFICATION  OF  ORE  DEPOSITS. 


75 


Davibree,    G.    A.      Lea     Eaux    souterraines    aux    Epoques 

ancieunes.     Paris,  1887. 
Les    Eaux    souterraines    a    I'Epoque   actuelle.     2    vols. 

Paris,  1887. 
De  Launay,  L.     Contribution  k  I'Etude  des  Gites  Metallifdres, 

Annales  des  Mines^  August,  181)7. 
Emmons,  E.     American  Geology,   134,   1853.     General    dis- 
cussion. 
Emmons,  S.  F.     "The  Structural  Relations  of  Ore  Deposits," 

Trans.  Amer.  Inst.  Min.  Eng.,  XVI.,  304.     Rec. 
"Notes  on  Some  Colorado  Ore  Deposits,"   Proc.    Colo. 

Sci.  Soc,  II.,  Part  II.,  p.  35. 
"On  the  Origin  of  Fissure    Veins,"     Proc.     Colo.   Sci. 

Soc,  II.,  p.  180.     Rec.     (See  also  R.  C.  Hills,   Idern, 

III.,  p.  177.) 
"The  Genesis  of  Certain  Ore  Deposits,"  Trans.  Amer. 

Inst.  Min.  Eng.,  XV.,  125.  Rec. 
"Geological  Distribution  of  the  Useful    Metals    in    the 

United  States,"  Trans.  Amer.  Inst.  Min.  Eng.,  XXII., 

52.     Rec. 
Eudlich,  F.  M.     Hayden's  Survey,  1873,  p.  276.    General  de- 
scription of  veins. 
Fairbanks,  H.  VV.     "The  Relation  between  Ore  Deposits  and 

their  Enclosing    Walls,"    Engineering   and  Mining 

Journal,  March  4,  1893,  p.  200. 
Foster,  C.  L.     "What  is  a  Mineral  Vein?"  Abstract  in  Oeol. 

Mag.,  Vol.  I.,  513. 
Fucbs,  E.,  et  De  Launay,  L.     Traite  des  Gites  Mineraux  et 

Metalliferes.     Paris,  1893.     Rec. 
Fox,  R.  W.     "Formation    of    Metallic    Veins    by    Galvanic 

Agency,"  Amer.  Jour.  Sci.,  I..  37,  199.    Abstract  from 

London  and  Edinburgh  Phil.  Mag.,  January,  1839. 
"On  the  Electro-Magnetic    Properties    of    Metalliferous 

Veins  in  the  Mines  of  Cornwall,"  Amer.  Jour.  Sci.,  I., 

20,  13(J,     Abstract  of  paper  before  the  Royal  Society. 
Glenn,  W.     "The  Form  of  Fissure  Walls,  as  Affected  by  Sub- 

Fissuring  and  by  the  Flow  of  Rocks,"   Trans.  Amer. 

Inst.  Min.  Eng.,  XXV,,  499,  1S95. 
Grimm,  J.     "Die  Lagerstatten  der  Nutzbaren  Mineralien," 

18G9. 


76 


KJ'JMPS  OA'/v  DEPOSITS. 


Groddeck,    A.    vou.    "The    Clrtssificatiou   of  Ore  Deposits," 

Enyineering  and  MiniiKj  Journal,   June  27,  18H5,  ji. 

4:57. 
"Die  Lelire  von  don  Lagerstatten  der  Erze,"  ls7;i.   Rec. 

(See  also  Enfjineeriug  and  Mining  Journal,  Jan.  3, 

1880,  p.  2,  for  a  review  of  same.) 
Hague,  A.  D.     "Mining  Industries,  Paris  Exposition,  1878." 
Henrich,  C.     "On  Faults,"  Eiujiueerimj  and  Mining  Jour- 
nal, Aug.  24,  1S81I,  p.  15S. 
Hunt,  T.  S.     "The  Geoguostical  History  of  the  Metals,  Trans. 

Anier.  Inst.  Mi)i.  Eng.,  I.,  W.W. 
"The  (3rigin  of  Metalliferous  Deposits,"  in  Chemical  and 

Geological  Essai/s. 
"Contrihutions   to   the   Chemistry  of   Natural   Waters," 

Anier.  Join:  Sic,  II.,  :il»,  17G. 
Julien,  A.  A.     "On  the  Part  Played  by  Humus  Acids  in  Ore 

Deposit,  Wall  Rock,  Gossan,"  etc.,  Froc.  Anier.  Assoc. 

Adv.  Sic,  1S70,  pp.  382,  885. 
Keck,  R,     "The  Genesis  of  Ore  Deposits,"  Engineering  and 

Mining  Journal,  Jan.  (J,  1883,  p.  3. 
"Review  of  Ore  Deposits  in  Various  Countries."    Denver, 

1802.      31  pages. 
Kemp,  J.  F.     "A  Brief  Review  of  the  Literature  on  Ore  De- 
posits," School  of  Mines  Quarterly,  X.,  54,  IIG,  32G; 

XL,  359  ;  XIL,  210. 
"On  the  Filling  of  Mineral  Veins,"   School  of  Klines 

Quurterhj,  October,  1S91. 
"The  Classification  of  Ore  Deposits,"  School  of  Minen 

Quarterli/,  November,  1802. 
"On  the  Precipitation  of  Metallic  Sulphides  by  Natural 

Gas,"  Engineering  and  Mining  Journal,  DecemlKr, 

1800. 
"An  Outline  of  the  Views  Held  To-day  on  the  Origin  of 

Ores,"  The  Mineral  Industry,  IV.,  755,  1805. 
Kimball,  J.  P.     "Our  Mineral  Interests,"  Memoirs  of  the 

American  Bureau  of  Mines. 
Kleinschmidt,   J.    L.      "Gedanken    ueber    Erzvorkommeii, " 

Berg-  und  Huet.  Zeit.,  1887,  p.  413. 
Koehler,  G.     "Die  Storungen  der  Gilnge,   Flotze,  u.  Lager," 

Leipzig,    1886.     Translated  by  W.    B.    Phillips    uuder 


'II 


iil 


CLASSIFirATIOX  OF  ORK  DEPOSITS. 


77 


title  of  "Irregularities  of  Lodes,  Veins  and  Beds," 
Engineen'uff  and  MiniiKj  Joiwnal^  June  ^5,  1H87,  p. 
454;  also  July  *^,  p.  4. 

Leconte,  J.     "Mineral  Vein  Formation  in  Progress  at  Steam- 
boat Springs,  compared  with  the  same  at  Sulphur  Bank," 
Anier.  Jour.  Sci.,  III.,  2r»,  42i. 
"Genesis  of    Metalliferous   Veins,"   Anier,    Jour.    Set., 
July,  1883.     See  other  references  under  "Mercury  *' 

Leconte,  J.,  and  Rising,  W.  B.  "The  Phenomena  of  Metalli- 
ferous Vein  Formation  now  in  Progress  at  Sulphur 
Bank,  Cal."     Amer.  Jour.  Sri..  July,  18S*,  p.  23. 

Moreau,  George.  "Etude  Industrielle  des  Gites  Metalli- 
feres,"  Paris,  1894.  Rec. 

Muller,  A.     Erzgange.     Basel,  1880. 

l\Innroe,  H.  S.  "List  of  Books  on  Mining,"  School  of 
Mines  Quarterly,  X.,  170. 

Necker.  "On  the  Sublimation  Theory,"  Proc.  Geol.  Soc.  of 
London,  Vol.  I.,  p.  303;  also  Ansted's  Treatise  on  Ge- 
ology, Vol.    II.,  p.  271.     Hist. 

Newberrj',  J.  S.     "The  Origin  and  Classification  of  Ore  De- 
posits," School  of  Mines  Quarterly,   I.,  March,  1880; 
Engineering  and  Mining  Journal,  June  19  and  July 
23,     1880;    Proc.    Amer.     Assoc.    Adv.     Sci.,    Vol. 
XXXIL,  p.  243,  1883.     Rec. 
"The  Deposition  of  Ores,"  School  of  Mines  Quarterly, 
v.,  320,  1884;  Engineering  and  Mining  Journal,  July 
19,  1884. 
"Genesis  of  Our  Iron  Ores,"  School  of  Mines  Quarterly, 
II.,  1,  1880;  Engineering  and  Mining  Journal,  April 
23,  1881.     See  aiso  under  "Iron." 
"Genesis  and  Distribution   of  Gold,"  School  of  Mines 
Quarterly,  III.,  1881;  Engineering  and  Mining  Jour- 
nal, Dec.  24  and  31,  1881.     Rec. 

Ochsenius,  Curl.  "Metalliferous  Ore  Deposits,"  Geol.  Mag., 
L,  310.     Hist. 

PearcG,  Rich.  "On  Replacement  of  Walls,"  Chem,  News, 
March  3,  1865. 

Penrose,  R.  A.  F.  "The  Superficial  Alteration  of  Ore  Depos- 
its," Journal  of  Geology,  II.,  288,  1804.     Rec. 


78 


KEMPS  ORE  1)EP(>SITS. 


Phillips,  J.  A.     "The  Rocki?  of  the  Mining  District  of  Corn- 
wall   and  their  Kolationa  to  MotulliforouH   Deposita," 
Quar.  Jour.  (Jeol.  Soc,  XXXI.,  :{iy. 
'*A    Contribution    to    the   HiHtory   of    Mineral   VeiiiH," 

Quar.  Jour.  Oeol.  6V>r.,  XXXV.,  ;}•.)(). 
"Connexion  of  Certain  Phenomena  with  the    Origin    of 

Mineral  Veins,"  Phila.  M(f<izine,  Deceniher,  1K71. 
"TreatiHeon  Ore  DepOHits,"  London,  lH8-i. 
Posepny,  F.     Archiv  fiir  praktische  Geologie,  I.  and  II. 

"The  Genesis  of  Ore  Deposits,"  Triuis.  Aiucr.  Jnsf.  M/n. 
Eng.,  XXIL,  (j;{.     Rec. 
Power,  F.  D.     "The  Classification  of  Valuable  ^Mineral   Dt- 

pusits,"  Trous.  AuHtralasian  Inst.  Min.  Eug.,  ISli*-.'. 
Pumpelly,  R.     Jo]r)iso)i\s  Encjfcl.,  Vol.  VI.,  p.  22.     Rec. 
Raymond,  R.  W.     "What   is  a  Pipe    Vein?"     EngineeriiKj 
and  Mining  Journal,  Nov.  2:},  ISTh,  p.  301. 
Translation  of   Lottner,    and  general  remarks  on   Clasi^i- 
fication,  Min.  Stat.  West  of  liocki/  Mountains^  18T(i, 
p.  447. 
Indicative  Plants,  Trans.  Amer.  Inst.  Min.  Eng.,  XV., 

G45. 
"Geographical  Distribution   of    Mining  Districts    in    the 
United  States,"  Idem,  I.,  p.  ;}3. 
Rickard,  T.  A.      "Vein-Walls,"    Trans.  Amer.  Inst.  Min. 

Eng.,  XXVI.,  193,  181)(;. 
Sandberger,  F.      " Untersuchungen    iiber    Erzgange,"    18H2; 
"Theories   of  the  Formation  of  Mineral  Veins,"    En(ii- 
neering  and  Mining  Journal,  March  15,  Ji2,  20,  18s4, 
pp.  11)7,  212,  232. 
"Untersuchungen  an  den  Erzgiiugen  von  Pribram  in  BiJli- 
meu,"  Sitzungsher.  der  Wiirzburger  Phys.  Med.  Ge- 
sellschaft,  1880. 
Neue  Beweise  fiir  die    Abstammung  der  Erze  aus  deiii 
Nebengestein,  Idem,  1883. 
Stelzner,  A.  W.     "Die  Lateralsecretions-Theorie  imd  ihre  Be- 
deutung  fiir  das   Pribramer  Gauggebiet,"   B.  and  H. 
Jahrbuch    der    K.    K.     Bergakademie    zu    Leoben, 
XXXVII. 
Tarr,  R   S.     "The  Economic  Geology  of  the  United  States," 
1894. 


VLAHSIFK'ATION  OF  ORE  DEPOSITS. 


70 


Vogt,  J.  H.  I  p.     "Bilduiig  vou  Ezlagerstutten  durch  Difforen- 

tiatloiiHprocesse   in  basischen  Eruj)tivniaginata,"  Zeit- 

schrift  f.  praktische  (Jeolfxjie,  1HU3,  pp.  4,  143,  257. 

Rec.  " 

"Ueber  die   Kieslagerstiltten   voni    Typus    Ruros,"   etc., 

Idem,  IH'.x;,  pp.  41,  117,  17:5.     Roc. 
'•The  Formation  of  Eruptive  Ore  Deposits,"    The  Min- 
eral Lid  list  I'!/,  IV.,  lHlt5,  pp.  743,  754.     Rec. 
"Uober  die  relative  Verbreituug  der  Eleinente,  besondors 
dor  Schwerinetalle,  nnd  iiobor  die  Coiiceutration  der  foiu 
vertlioilten    Metal IgehalteH   zu    Erzlagerstiltten,"    Zeit- 
sdirift  fi'ir  prakt.  (Jcoloyie,  August,  ISSiH,  to  January, 
1S1U>,  and  later.     Rec. 
Wabuer,  R.     "Ueber  die  Eintbeilung  der  Minerallagerstatten 
naoh  ibrer  Gestalt,  sowie  die  Anwendung  und  die  Be- 
nutznng    der  Worte,   Lager    und   Flotz,"   Berg-    iind 
Huet.  Zcif.,  Jan.  i>,  ISin,  p.  1. 
Wadswortli,  M.  E.     "Tbe  Tlioories  of  Ore  Deposits,"  Proc. 
Boston  Soc.  Nat  Hist.,  1884,  p.  1S)7.     Rec. 
"The  Lateral  Secretion  Tbeor}'  of  Ore  Deposits,"  Enc/i- 

neering  and  Milling  Journal,  May  17,  1884,  p.  304. 
"Classification  of  Ore  Deposits."    Rep.   of  Mich,   State 
Geologist.  ISKl-'.)'^,  p.  144.     Rec. 
Whitney.  J.  D.     "Remarks  on  tbe  Changes  which  take  place 
in  tbe  Structure  and  Composition  of  Mineral  Veins  near 
the  Surface,"  Amer.  Jour.  Sci.,  ii.  XX.,  53. 
"Metallic  Wealth  of  the  United  States,"  1854.     Rec. 
Whittlesey,    C.     "On  tbe   Origin   of  Mineral  Veins,"  Proc. 

Amer.  Assoc.  Adr.  Sci..  XXV.,  213. 
Williams,   Albert.      "Popular  Fallacies  Regarding  the  Pre- 
cious ]\retal  Ore  Deposits,"  Fourth  Ann.  Rep,  Director 
U.  S.  Geol.  Survey,  pp.  257-278. 


Ki 


PART  II. 


THE    ORE    DEPOSITS. 


CHAPTER  I. 

THE  IRON   SERIES    (iN  PART)— INTRODUCTORY    REMARKS   ON 
IRON    ORES— LIMOMTE— SIDERITK. 

GENERAL   LITERATURE. 

Biikinbine,  J.  "Prominent  Sources  of  Iron  Ore  Supply," 
Trans.  Amer.  Inst.  Miu.  Eng.,  XVII.,  715.  Statis- 
tical; Rec. 
"The  Production  of  Iron  Ores  in  Various  Parts  of  the 
World."  Sixteenth  Ann.  Rep.  Dir.  U.  S.  Geol. 
Survey.  Part  III.,  21.     Rec. 

Chester,  A.  H.  "On  the  Percentage  of  Iron  in  Certain  Ores," 
Trans.  Anier.  Inst.  Min.  Eng.,  IV.,  211). 

Dunuington,  F.  P.  "On  the  Formation  of  the  Deposits  of 
Oxides  of  Manganese, "  Anier.  Jour.  Sci.,  iii.,  XXXVL, 
175.     The  paper  treats  of  Iron  also. 

Hewitt,  A.  S.     "Iron  and  Labor,"  Trans.  Amer.  Inst.  Min. 
Eng.,  XVIII.     The  paper  contains  valuable  statistics. 
"A  Century  of  Metallurgy,"  Idem,  V.,  I(i4. 

Hunt,  T.  S.  "The  Iron  Ores  of  the  United  States."  Idem. 
XIX,:}. 

Kimball,  J.  P.  "Genesis  of  Iron  Ores  by  Isomorphous  and 
Pseudomorphous  Replacement  of  Limestone,"  Anier. 
Jour.  Sci.,  September,  1801,  p.  231.  Continued  in  Amer. 
Geologist,  December,  1891. 

Julien,    A.    A.     "The  Genesis  of  the  Crystalline  Iron  Ores," 
Trans.  Phil.  Acad.  Nat.  Sci.,  1882,  p.  335;  Engineer- 
ing and  Mining  Journal,  Feb.  2,  1884. 
"Origin  of  the  Crystalline  Iron  Ores,"    Trans.    N.    Y. 
Acad.  Sci.,  II.,  p.  (1;  Amer.  Jour.  Sci.,  iii.  XXV.,  470. 

Losley,  J.  P.  "The  Iron  Manufacturers'  Guide,"  18G0.  Hist. 
Rec. 

Newberry,  J.  S.      International  Review,  November  and  De- 
cember, 1874. 
"Genesis  of  the  Ores  of  Iron,"  School  of  Mines  Quar- 


84 


KEMP'S  CUE  DEPOSITS. 


terly.   November,   1880.     Rec.     Amer.  Jour,  Sci.^  iil., 
XXI.,  80. 
"Genesis  of  the  Crystalline  Iron  Ores,"   Trans.   N.    Y, 
Acad.  Sci.,  II.,  October,  1882.     Rec. 

Newton,  H.  "The  Ores  of  Iron:  Their  Distribution  with  Ref- 
erence to  Industrial  Centers,"  Trans.  Amer.  Inst.  Min. 
Eng.,  IIL,  3(!0. 

Pumpelly,  R.,  and  Others.  Tenth  Census,  Vol.  XV.,  1886,  es- 
pecially pp.  3-17.     Rec. 

Reyer,  E.  "Geologie  des  Eisens,"  Oest.  Zeit.  f.  B.  und  H., 
1882,  Vol.  XXX.,  pp.  8'.»,  109. 

Rop-ers,  W.  B.  "On  the  Origin  and  Accumulation  of  the  Pro- 
tocarbonate  of  iron  :n  the  Coal  Measures,"  Froc.  Bos- 
ton Soc.  Nat.  His.,  185G. 

Smock,  J.  C.  "On  the  Geological  Distribution  of  the  Ores  of 
Iron,"  Trans.  Amer.  Inst.  Min.  Eng.,  XII.,  130. 
"Iron    Mines    and    Iron   Ore    Districts    in  New  York," 
Bull.  N.  Y.  State  Museum,  June,  1880.     Rec. 

Swank,  J.  M.     Chapters  on  Iron  in  Mineral  Resources^  U.  S. 
Geol.  Survey,  since  1883. 
"History  of  the  Manufacture  of  Iron  in  All  Ages."     1801. 

Whitney,  J.  D.     "Metallic  Wealth  of  the  United    States," 
1854,  p.  425.     Hist. 
"On  the  Occurrence  of  Iron  in  the  Azoic   System,"  Pvoc. 
Amer.  Assoc.  Adv.  Sci.,  1855,  209;  Amer.  Jour.  Sci., 
ii.  XXII.,  38. 

Winchell,  N.  H.  and  H.  V.  "The  Iron  Ores  of  Minnesota," 
Bull.  Xo.  6,  Mi  nil.  Geol.  Survey,  1891.  Part  IV. 
contains  an  exhaustive  review  of  methods  of  origin,  and 
Part  V.  a  very  complete  annotated  bibliography. 


Table  of  Vie  Iron  Ores,  Linionite,  Siderite,  Hematite, 

Magnetite,  Pi/rite. 

Fe. 

HgO. 

COg. 

S. 

Liinonite  (browu  hematite,  bog  ore),  2Fe20s 
311,0 

59.  Vo 

14.4 

Sidente    (Spathic   ore,    clay-ironstone,  black- 
band)  FeCO, 

4H.27 

37.93 

Hematite  (red  and  sjiecular),  FegOj 

Magnetite,  FeO,  FeoOg,  or  Fe304    

TO.O 
72.4 



Pviite,  FeSo 

46.7 

riS  3 

THE  IRON  SERIES  {IN  PART). 


85 


2.01.01.  No  one  of  the  iron  ores  ever  occurs  pure  in  large 
amounts.  Only  a  few  closely  approach  this  condition.  The 
largest  quantity  of  rich  ore  as  yet  mined  in  the  United  States 
was  doubtless  obtained  from  the  Lovers'  Pit  opening,  oper- 
ated bj'  VVitherbee,  Sherman  &  Co.,  on  Barton  Hill,  near 
Mineville,  N.  Y.  The  pit  yielded  4(), ()(»(»  tons  of  magnetite 
that  averaged  08.0%  Fe,  with  many  carloads  at  7'2%.  The 
niioaceous  specular  of  the  Republic  mine,  Mich.,  is  said  to 
liave  been  shipped  an  entire  season  at  Oi)%.  The  Min- 
nesota mines,  near  Tower,  Minn.,  have  cleared  many 
cargoes  at  08  to  08.4"o.  The  richest  are  the  magnetites 
and  specular  hematites,  and  many  mines  of  the  Lake  Cham- 
plain  district  have  produced  the  former,  and  Lake  Superior 
mines  the  latter,  at  03  to  05%,  or  even  more.  The  separated 
ores  in  the  Lake  Champlaiu  district  run  about  05%'.  The 
iiuseparated  ores  have  much  less,  and  indeed  all  percentages 
from  50  to  05.  Thus  the  lump  ore  (shipped  as  mined)  from 
Cliateauga}',  N.  Y.,  has  about  5()"o.  The  Cornwall  (Pa.) 
magnetite  holds  even  less.  The  Clinton  red  hematites  from 
New  York  atl'ord  about  44%  in  the  furnace,  as  the  result  of 
long  experience.  The  limonites,  as  u.sually  mined,  produce 
from  4(1  to  50%.  The  crude  spathic  oies  are  the  lowest  of  all, 
and  in  the  variety  black-band  may  even  be  about  ;](»%.  They 
are  easily  calcined,  however,  and  on  losing  their  carbonic  acid, 
moisture  and  bituminous  matter  the  percentage  of  iron  rises  a 
third  or  more.  A.  H.  Chester  foimd  in  18T5,  as  the  result  of 
an  endeavor  to  determine  the  average  yield  of  certain  standard 
ores  in  the  furnace,  Lake  Superior  specidar,  0Ji.5^o;  Lake 
Superior  limonite,  40.5%,  which  is  much  too  low  to  be  sala- 
ble to-day;  Rossie  (N.  Y.)  red  hematite,  54.5%;  Wayne 
County  (k  Y.)  Clinton  ore,  40%. 

2.01.02.  The  common  impurities  in  iron  ores  are  the  com- 
mon elements  or  oxides  that  enter  most  largely  into  rocks,  and 
those  which  make  up  the  walls  of  the  deposit  are  usually  the 
ones  that  appear  most  abundantly  in  the  ore.  Silica  (SiOa),  alu- 
mina (AI2O3),  lime  (CaO),  magnesia  (MgO),  titanium  oxide 
(TiO,).  carbonic  acid  (CO2),  and  water  (H2O)  appear  in  large 
amounts  and  determine  to  a  great  extent  the  character,  fluxing 
properties,  etc.,  of  the  ore.  With  these,  and  of  more  far-reach- 
ing influence,  are  smaller  amounts  of  sulphur  and  phosphorus. 


86 


EEMP'ii  OliE  BEPOtilTS. 


^i^ 

1 

m 

The  last  two  and  titanium  chiefly  determine  the  character  of 
the  iron  which  is  yielded  in  the  furnace,  and  are  the  first  foreign 
ingredients  sought  by  analysis.  The  sulphur  is  present  in  pyrite, 
the  phosphorus  in  apatite.  As  is  well  known,  0. 1  "o'  of  phosphorus 
)3  set  as  the  extreme  limit  for  Bessemer  pig  irons,  and  as  ores 
for  these  command  the  best  market,  they  are  eagerly  sought. 
To  obtain  the  allowable  limit  of  phosphorus  in  the  ore,  its  per- 
centage in  iron  is  divided  by  1000.  Thus  a  (i5.o"o  ore  should 
not  have  over  0.0(J.5"o  phosphorus  to  be  ranked  as  Bessemer.  If 
at  the  same  time,  with  sufficiently  low  phosphorus,  the  ganguo 
in  highl}'  siliceous,  a  composition  desirable  for  Bessemer  prac- 
tice, ores  have  been  of  value,  altliough  of  comparatively  low 
grade,  and  remotely  situated.  For  Lake  Superior  ores  the 
buyers  insist  to-day  on  a  still  lower  Bessemer  limit,  and  do  not 
call  anv  ore  over  0,or)^"o  phosphorus  a  strictly  Bessemer  ore.  The 
ore  is  required  to  be  low  enough  to  carrj'  the  phosphorus  iu 
both  fuel  and  flux,  and  still  yield  a  pig  iron  of  not  over  0.1  "o  P. 
On  the  other  hand  a  moderate  amount  of  phosphorus  is  not 
only  no  drawback  for  ordinary  foundry'  irons,  and  such  as  are 
subjected  to  tool  treatment,  but  is  a  prime  necessit5^  Excessive 
amounts  are  desired  onl}'  for  weak  but  very  fluid  irons  or  for 
the  basic  steel  process.  Considerations  like  these,  which  are 
rather  metallurgical  than  geological,  largely  determine  the 
availability  of  a  deposit,  and  to  some  extent  the  present  loca- 
tions of  the  mining  districts. 

2.01. o;5.  Iron  itself  is  one  of  the  moat  abundant  and  widely 
disseminated  elements  entering  into  the  composition  of  the 
earth.  Several  writers  have  attempted  to  detluce  the  general 
composition  of  the  outer  portions  of  the  globe,^  but  the  most 
reliable  computation  is  that  of  F.  W.  Clarke  in  Bulletin  78 
of  the  U.  S.  Geol.  Suni,  pp.  34-43.  The  crust  to  a  depth  of 
ten  miles  below  sea- level  is  tiie  subject  of  the  estimate,  and  tlio 
air  and  ocean  are  included.  The  com])osition  of  the  solid  crust 
is  reached  by  averaging  analyses  of  igneous  and  crystalline 
rocks,  8S0  iu  all;  3:U  from  the  United  States,  75  from  Euro))(". 
and  486  from  all  (juarters.  Igneous  rocks,  being  the  ultimate 
source  of  the  others,  furnish  a  good  average.     The  final  result 


•  Compare  Alex.  Winrhcll,  Geological  Studies,  pp.  10-20,  and  Prcst- 
wich's  Geology,  1.  p.  10 — both  of  wliich  were  quoted  in  the  first  edition  of 
this  work. 


TUE  IRON  SERIES  {IN  PART). 


87 


is  the  followingjin  which  amounts  less  than  0.01%  are  omitted. 
The  total  is  100. 


0 49.98 

Si 25.30 

Na 

K 

H 

Ti 

C 

CI.  Br. . . . 

....2.28 
....2.23 
....0.94 
....0  30 
....0.21 
....0.15 

P 

Mn. . . . . 

S 

Ba. . . . . 

N 

Cr 

0.09 

0.07 

AI 7.26 

Fe 5.08 

0.04 

0.03 

Ca 3.51 

Mg 2.50 

0.03 

0.01 

From  this  it  is  seen  that  iron  is  much  the  most  abundant 
of  the  useful  metals,  and  that  its  common  impurities,  titanium, 
pliosphorus  and  sulphur  are  all  present  in  appreciable  amounts. 

3.01.04:.  A  general  comparison  of  tabulated  aual3'ses  of 
igneous  rocks  (Roth's  Gesteinsanalysen  and  Allgeineine 
Geologie)  shows  that  granites  contain  0.0-7%  iron  oxides,  por- 
phyries 0.0-14%,  rhyolites,  0.0-8%,  diorites  and  diabases  4-10%, 
andesites  3-15%,  basalts  12-20,'*o'.  Limestones  invariably  have 
■dt  least  small  amounts,  and  at  times  very  considerable  percent- 
ages. Sandstones  are  often  low,  but  not  seldom  are  stained 
tlu'ough  and  through.  The  metamorphic  rocks  offer  close 
analogies  to  the  igneous.  In  general  distribution  and  in  quan- 
tity, iron  leads  the  list  of  the  distinctively  metallic  elements. 
Its  peculiar  property  of  possessing  two  oxides,  of  different 
chemical  quantivalence,  assists  greatly  in  the  formation  of  ores 
and  the  general  circulation  of  the  metal.  This  is  set  forth 
under  the  following  examples: 

LIMONITE. 

2.01.05.  Example  1.  Bog  Ore. — Beds  cf  limonite,  super- 
ficially formed  in  marshes,  swamps,  and  pools  of  standing 
water.  The  general  circulation  of  water  through  the  rocks 
enables  it  very  frequently  to  take  up  iron  in  solution.  Ferru- 
ginous minerals  are  among  the  first  and  easiest  that  fall  a  prey 
to  alteration.  Carbonic  acid  in  the  water  aids  in  dissolving  the 
iron,  which  thus,  in  waters  containing  an  excess  of  CO^,  passes 
into  solution  as  the  protocarbouate  FeCOa.  Organic  acids  may 
also  play  a  part.  The  alteration  of  pyrito  affords  sulphuric 
acid  and  ferrous  sul])hate,  and  the  latter  enters  readilj'  into 
solution.  On  meeting  calcium  carbonate,  both  ferric  and  fer- 
rous sulphate  are  decomposed, yielding  in  the  first  case  calcium 
sulphate,  ferric  hydrate,  and  carbonic  acid;  in  the  second,  if 


matter 
f'o  state 
filial]  (j|i 
ft'rnigiii 
swamps, 
excess  o 

of   OXJg( 

atom  of( 
(Irated  o: 
liitter  for 
niiilates 
Hud   as    I 
it  remain 
"lay  cove 
exists  vvhi 
ore  benea 
fartli  aud 
\vJiicJi  one 
«"ons  of  h 
bodies  are 
i'ei'centago 
^^ashed  in, 
I'lii'sphoru! 
and  the  j)J 
t'>y  to  be 
^liiJIiciti. 
*lt'|Josits 
otliers  miw 

■-■"l.or. 
tJiii^^nt  anc 
^ered  uodu 
^y  a  bed  tl 

■■'  «".   C.    K 

^''"'/'    CCIIKK. 

Sitrrri,,  i,s})j{_ 


TIIK  IRON  SKRIE8  {IJV  PART). 


89 


ftir  is  absent,  ferrous  carbonate  and  calcium  sulpbate,  but  on 
tlie  admission  of  air,  ferric  hydrate  soon  forms.' 

•^.01.00.  Bodies  of  limouite  that  become  exposed  to  a  reduc- 
ing action  from  the  favorable  presence  of  decajing  organic 
matter  likewise  furnish  the  protocarhonate.  In  general  it  may 
1)0  stated  that  free  oxygen  must  be  absent  or  present  only  in 
small  quantity  where  solution  takes  place.  Sooner  or  later  the 
ferruginous  (or  chalybeate)  waters  come  to  rest,  especially  in 
swamps.  The  protosalt  is  ex})i)sed  to  the  evaporation  of  the 
excess  of  COa,  that  held  it  in  solution,  and  also  to  the  action 
of  oxygen.  Two  molecules  of  carbonate,  together  with  one 
atom  of  oxygen  and  some  water,  break  up  into  C(\.,  and  the  hy- 
drated  oxide  2  Fca^);),  -i  H-O,  or  some  related  molecule.  The 
latter  forms  as  a  scum  and  then  sinks  to  the  bottom  and  accu- 
nudates  in  celluUw  masses.  The  ses(iuioxide  is  insoluble, 
and  as  against  ordinary  waters  free  from  reducing  agents 
it  remains  intact.  Deposits  of  mud  and  peat  forming  above 
may  cover  the  beds  with  a  protecting  layer.  Hardly  a  bog 
exists  wliich  does  not  show,  wlien  cut  in  cross  section,  the  ln)g 
ore  beneath.  Frequent  associates  of  the  ore  are  diatomaceous 
earth  and  shell  marl,  contributed  by  the  remams  of  organisms 
which  once  inhabited  the  waters.  At  times  excellent  impres- 
sions of  leaves  and  shells  are  preserved  in  the  ore.  Such  ore 
bodies  are  not  often  practicably  available  on  account  of  the  low 
percentage  in  iron,  due  to  the  abimdance  of  sand  and  silt 
washed  in,  and  to  the  frequent  large  amounts  of  sul})hur  and 
phosphorus  whicli  they  contain.  The  sulphur  is  present  in  pyrite 
and  the  phosphorus  in  vivianite,  sometimes  in  sutticient  quan- 
tity to  be  visible  as  at  Mullica  Hill,  N.  J.,  where  the  variety 
Miillicite  is  found.  In  certain  parts  of  the  countr}-  bog 
dt'))()sits  have  been  utilized  and  under  peculiar  conditions 
otliors  may  yet  be. 

■J. 01. 07.  In  eastern  North  Carolina  bog-ore  beds  are  fre- 
quent and  are  found  lying  just  below  the  grass  roots.  Scat- 
tered nodules  occur  in  the  overlying  soil,  which  are  succeeded 
by  a  bed  three  feet  or  less  in  thickness,  resting  on  sand.^ 

'  y.  V.  Dunnington,  Ainer.  Jour.  ScL,  iii.,  XXXVI.,  17(i.  Exi)eriments 
111  and  11. 

■'  W.  C.  Kerr,  Geoloijtj  of  North  Carolina,  1875,  p.  218.  B.  Willis, 
Tnith  Cnmts,  Vol.  XV.,  p.  ;503.  H.  B.  C.  Nitze,  Bull.  I.  N.  C.  Geol. 
Siinrii.  1893. 


90 


KEMP'S  DUE  DEPOSITS. 


lu  HuITh  Valley  and  Handcart  (iulcli,  Park  County,  Colo., 
interesting  and  extensive  deposits  of  limonite  are  in  ac- 
tive prnceHs  of  formation.  The  iron  conies  from  neighboring^ 
great  beds  of  j)yrite.' 

Bog  ore  of  good  (piality  has  recently  been  reported  from  the 
vicinity  of  Great  Falls,  Mont.* 

At  l\)rt  Townsend  Bay,  in  the  vicinity  of  Puget  Sound, 
and  at  the  Patton  mines,  near  Portland,  Ore.,  the  ores  are  of 
such  (juality  as  to  be  available.'* 

Attention  has  been  lately  directed  to  the  great  deposits  of  bog 
ore  in  the  Three  Rivers  district  of  the  Province  of  (Quebec  in 
Canada,  Three  Kivers  is  on  the  St.  Lawrence  about  midway 
between  jVIontreal  and  Quebec,  but  the  district  which  furnishes 
the  bog  ores  extends  from  northeast  of  (Quebec  to  a  point  west 
of  Ottawa,  an  area  stated  by  Griffin  to  be  -lOO  miles  long  l)y 
40  to  (50  broad.  The  drainageof  tho(jld  Arcliean  beightsof  tlie 
Laurentides,  the  range  that  suggested  the  name  Laurentiaii, 
crosses  the  belt,  and  being  more  or  less  laden  with  ferruginous 
solutions  it  deposits  the  ore  in  swamjis.  streams  and  lakes, 
wherever  the  water  is  for  a  time  stationary  or  choked  with 
vegetation.  The  ore  beds  furnish  ideal  illustrations  of  bog-ore 
deposits  in  all  their  foi'ms.  Beginning  as  a  light  film,  the  uie 
gradually  accumulates  on  the  bottom,  where  it  hardens  into 
thick  crusts.  These  are  exposed  to  the  sun  in  the  dry  Reason 
in  the  shallower  reaches,  and  become  very  hard  cakes.  Dur- 
ing the  succeeding  wet  season  they  are  buried  again  under 
more  ore,  or  sand  and  ore,  until  the  thickness  attained  i> 
very  considerable.  The  ore  is  precipitated  also  in  ruuniut; 
water,  and  has  been  obtained  from  ravines  in  goodly 
amount.  Even  in  the  pipes  used  at  the  furnace  at  Radnor 
Forges  for  conveying  the  necessary  water  supply  from 
the  neighboring  Riviere  au  Lard,  the  limonite  deposits. 
The  river  flows  from  the  sw'amp  called  Grand  Pie,  in 
the  midst  of  which  is  a  shallow  lake  called  Lac  a  la  Tortue. 
Ore    is  dug   in  the  swamp  and  dredged   in  the   lake.      Tlje 

'  R.  Cliauvenet,  " Tlie  Iron  Resources  of  Colorado,"  Trnus.  Amer.  Iniit. 
Min.  Eh(j.,  XVIII.,  2ll().  "Note.s  on  Iron  Prospects  in  Northern  Colo 
rado,"  Ann.  Rep.  Colo.  School  of  Mi iici,  188(5. 

'  Mineral  Eesoiwces,  U.  S.  Geol.  Stirvej/,  1888,  p.  34. 

3  B.  T.  Putnam,  Tenth  C.'».s'h.s\  Vol.  XV.,  p.  496. 


Till-:  I  HON  si:  It  IKS  {IN  PAUT). 


91 


siijjply  18  renewed  after  l)eiii^  removed.  'Ilie  depoHitH  jiresent 
iiiiiny  analogies  with  tlioHe  of  the  Swedish  lakeH,  later  men- 
tioned, l)nt  they  supply  caked  ore  rather  than  the  0(")litie  form 
(if  the  latter.  The*  iron  induMti-y  hej^an  in  ther(>gion  in  Kod  and 
li.is  eontinned  more  or  U'hh  intermittently  to  dati'.'  I'ht*  iron 
furnished  has  espeeial  exeelleuee  for  oar-wheels  and  chilled 
(MstiuKa.  The  lake  ores  .seem  to  run  somewhat  richer  than  those 
<it  the  bogs.  The  latter  contain  al)out42.r)",;  Fe,  the  former  4t>%. 
iloth  have  a  little  over  ():.\%  P  ami  less  than  O.L",^  S.  These 
ore  bodies  are  of  great  scientific  interest,  for  they  illustrate  (as 
lias  been  recognized  for  many  years)  tiie  formation  of  bodies  of 
dtlier  kinds  of  iron  ores  when  in  aedimeutary  aeries,  and  even 
when  metamorphosed. 


Fiu.  8. — Crosn-seetion  of  the  Profmer  irnu   iin'iir,    nvar  Porflnnd,   Ore., 
sJwwiiig  the  bed  of  liniotiifc  hctirrcn  tiro  sticfis  of  Ixisalf.     After 
'  B.  T.  riitiKim,  Tenth  Census.  Vol.  A'l'!  p.  4fl(i. 

•^.01.08.  A  somewhat  different  variety*  of  Example  1  results 
when  the  ferruginous  waters  come  to  rest  in  the  superficial  hol- 
lows of  the  rock  which  has  furnished  the  iron.  ])epressions 
ill  tlie  serpentines  of  Staten  Island.  N.  Y.,  contain  such  deposits, 
and  the  ore  has  been  referred  by  N.  L.  Britton  to  the  leaching 
of  tlie  underlying  rock.  It  contains  a  notable  percentage  of 
cliromium,  which  is  known  to  be  an  element  in  the  serpentine. 
The  mines  have  been  in  former  years  quite  large  producers. 
Similar  limonites  occur  at  R3"e,  N.  Y.^ 

'  See  especially,  P.  H.  Griffin,  "  Tlie  Mauiifacture  of  Charcoal-iron  from 
the  IVif;  and  Lake-ores  of  the  Three  Rivers  District,"  Trans.  Amcr.  Inst. 
Mia.  Kag.,  XXI.,  974.  Also  J.  H.  Bartlett,  Trans.  Anier.  Inst.  Min. 
Enif..  XIV.,  508.  =■  N.  L.  Britton,  School  of  Mines  Quarterly,   May, 

18bl.    Compare  also  ^7Jier.  Jour.  Sci.,  iii.,  XX.,  33,  and  XXII.,  488. 


( 

: 

1 

99 


JxhMJ'S  DUH  J)J:J'(>S/TS. 


At  tho  ProHHcr  mines,  vvnv  i'ortland,  Ont.,  dcpoHitH  of  liino- 
nito  aru  I'oimd  in  the  Huperficial  hollown  of  a  Tertiary  basalt  of 
tlu*  Cascade  range.  Tiie  ore  contains  roots  and  1  ranks  of  trees, 
atal  is  coveied  by  a  later  How  of  basalt.  Similar  bodies  of 
limonite  i-esnlting  from  basalt  are  known  iu  the  Uerman  prov- 
ince of  Hesse,  and  in  Ireland.' 

2.(>I.(tJi.  Tho  limouito  sand,  or  oitlite,  that  forms  iu  the 
Swedish  lakes  about  ten  nn'tersfrom  the  banks  and  in  water  up 
to  ten  meters  in  deiitli  is  another  variety  of  this  type.  A  layer 
half  a  meter  and  less  in  thickness  accunudates  every  fifteen  to 
thirty  years,  and  is  periodically  dredged  out.  The  ore  is  j)recipi- 
tated  first  as  a  slime  that  breaks  up  afterward  into  small  oou- 
crotions.  It  has  been  thought  that  tiie  formation  (jf  these  and 
gimilar  bodies  of  limonite  has  been  aided  by  small  algju  and 
other  plants  or  microscopic  organisms." 

•^'.(il.lO.  Example -i.  Bodies  of  limonite  in  cavities  of  fer- 
ruginous rocks,  on  the  outcrop,  or  below  the  surface,  which 
have  resulted  either  from  the  alteration  of  tho  rock  in  situ  (ir 
from  its  i)artial  replacement  by  limonite.  Residual  clay, 
tjuart/,  and  other  remains  of  alteration  usually  occur  with  tho 
ore.  Ferruginous  limestones  are  tho  conunonest  sources  of 
such  deposits,  but  otlun"  rocks  may  aiford  them.  The  deposits 
are  not  limited  to  any  one  get)logical  series,  but  in  different 
parts  of  the  country  occur  wherever  the  conditions  have  been 
favorable.  Some  of  the  ore  may  have  been  brought  iu  by  sub- 
terranean circulations  which  have  leached  the  neighboritig 
rocks.  Considerable  limonite  has  also  resulted  from  the  weath- 
ering of  clay-ironstone  uodules   and    black-band   beds  iu  tlie 

•  B.  T.  Patnani,  Tcvth  Cnm(N,  Vol.  XV..  p.  16,  ami  J.  S.  Diller,  "A 
Geolof^ical  KtHioniiaissanee  iu  N'orthwestern  Orcj^on,"  Eiijlitceiith  Ann. 
Rep.  U.  8.  Geol.  Survey,  Part  II.,  on  the  Oregon  ore;  Tasche,  Bcrrj.-  wid 
Iliiff.  Zcit.,  188(5,  p.  20!);  also  Wurtemberger,  NcucsJahrb.,  18(57,  p.  (is,-,, 
on  tlie  Ile.ssian  ores;  Tate  and  lIoldtMi,  "Ou  the  Iron  Ores  Associated  with 
the  Basalt  of  Northeastern  Ireland,"  ^uar.  Jour.  Geol.  Soc,  XXVI.,  IT)!. 

"  F.  M.  StapfT,  Ziit.icln:  d.  d.  (frohxj.  Gn^rllxrli.,  18(50,  Vol.  XVITI.,  j).  S, 
on  the  geology  of  the  ores.  Sjogrun,  Boy.-  und  IJi'ttt.  Zcit.,  18(5."),  p.  IK!. 
on  the  agency  of  algae.  On  the  general  formation  of  bog  ores  the  follow 
ing  papers  are  of  interest:  G.  .1.  Bnisli  and  ('.  S.  Rodman,  "  Observations 
on  the  Natives  Hydrates  of  Iron,"  Avwr.  Jour.  Sci.,  ii.,  XLIV.,  21i);  J.  S. 
Newberry,  School  of  Minen  Qnarterlij,  November,  1880;  J.  Roth,  Clmii 
und  Phi/s.  Geolocfie,  I.,  pp.  58,  97,  321;  F.  Senft,  Humus,  Marsch,  Turf- 
und  Liinonit-hildimgen. 


('arb(. 

<|H(«ntl 

liuioiii 

tative  : 

nia.sses 

cracks 

Cures  o 

a  lioljo 

27.\  ;{(;! 


I'Ki.    9.  —  ,' 

illu.\ 


•^.01.11. 
^.\l'e  the  o 
faking  up 
'".v,  and  i; 

^'"'■se  of  ea 
'^''•'Rinia,  ' 
^\-e.stern  Pe 
^"'"in  the  hi 
"isli  small 
-^IcCroath 


Till':  llioy  S  Mil  IKS  (LV  IWIIT). 


\)'A 


(  arlioniforouH  Hystoni  (to  Ik»  niontionod  later),  and  not  infre- 
i|iit'ntly  from  the  alteration  of  nodular  nuiHHtw  of  pyriteH.  The 
linionite  is  in  oellular  linnps,  iu  pipew,  pots,  and  variouH  iini- 
tativo  forms  which  often  have  a  heaiitifnl  Instri^  The  hollow 
iiiass«»s  have  in  general  residted  from  the  fillinji;  of  reticulated 
Clacks  in  shatt(n'«M|  rock.  TIk*  ort*  thus  (U'posits  around  the 
ci'ii's  of  country  rock,  which  afterward  are  removed,  leaving 
a  hollow  shell,  or  goode.  (See  Tenth  Ceusnn,  Vol.  XV'.,  pp. 
5}7A,  :)Ct),  370.) 


I'Ki.    9, — Siction   iif  the  Hurst  limoidte  bank,    Wi/t/ie.   ('omit//,    Virginia, 

illudrating  the  replacement  of  shattered  limentune  with  liiuouite 

and  the  fornuttion  ofgeodis  of  ore.     After  E.  It.  Benton, 

Tenth  Census,   Vol.  XV.,  p.  2T5, 


'  i;l 


2.01.11.  Reserving  the  Siluro-Cambrian  limonitesfor  a  sub- 
type the  ore  bodies  are  described  in  order  from  east  to  west, 
takij]g  up  first  the  Allegheny  region,  then  the  ]\Iississippi  Val- 
li'v,  and  lastly  the  Rocky  Mountains.  The  limonite8  of  New 
Knyland  and  New  York  belong  to  the  present  subtype,  as  do 
tluwe  of  eastern  Pennsylvania  and  the  more  important  ones  in 
^'il•ginia,  Tennessee,  Georgia  and  Alahama.  In  central  and 
western  Pennsylvania,  however,  not  a  small  amount  is  obtained 
fioin  the  higher  lying  terranes.  The  Hudson  River  slates  fur- 
nish small  amounts  in  Franklin  County,  which  are  thought  by 
ilcCreath  to  have  lesulted  from  the  alteration  of  nodules  of 


V 


u 


KEMP'S  ORE  DEPOSITS. 


pyrites.*  The  Medina  sandstones  contain  highly  ferruginous 
portions  in  Huntingdon  County."  The  lower  Helderberg  and 
Oriskany  are  locally  quite  productive  in  Blair  County, 
aifording  several  great  banks  of  ore.^  The  Oriskany  is  of 
greater  importance  in  Virginia  than  in  Pennsylvania.  East 
of  these  last-mentioned  exposures,  and  in  southern  Carbon 
Country,  in  a  bed  of  paint  ore  between  the  Oriskany  and  the 
Marcellus.*  The  Marcellus  is  the  most  productive  of  tlie 
Devonian  stages.  It  affords  considerable  ore  in  Perrj'  County,^ 
Juniata  Count3%  Mifflin  County,  Huntingdon  County.* 
Fulton  County"  and  Franklin  County."  All  these  are  in 
southern  Pennsylvania.  Lesley  states"  that  the  ore  is  weathered 
carbonate.  As  shown  under  Example  4,  bedsi  of  carbonate  ore 
occur  in  Ulster  County,  New  York,  in  the  Marcellus.  (Addi- 
tional details  on  the  above  Pennsylvania  deposits  will  be  found 
ill  the  geological  reports  on  the  particular  counties.) 

:i.Ol.  i;2.  As  already  remarked,  the  greater  part  of  the  limon- 
ites  in  "Virginia  belong  under  the  Siluro-Cambrian  division 
and  are  there  described,  but  in  the  James  River  B.-^sin,  on  Pin-- 
gatory  and  May's  Mountains,  there  are  deposits  in  sandstones 
of  the  Clinton."*  Other  limonitebeds  occur  in  the  Oriskany  on 
Brushj'  Mountain  (Longdale  mines),  on  Rich  Patch  Mountain 
(Low  Moor  mines,  called  by  Lyman,  Marcellus),  on  Warm 
Spring  Mountain,  and  on  Peter  Mountain.  In  the  Shenandoah 
Valley,  on  Massanutton  Mountain,  the  limonite  is  referred 
by  Prime  to  the  Clinton  stage."  On  North  Mountain  it  liesiu 
the  Oriskany,  according  to  Campbeir'"  and  on  the  Great  North 
Mountain  in  the   Upper   Silurian.    Considerable  oxide  of  zinc 

'  Second  Penn.  Geol.  Survey,  M3,  p.  x. 
"  McCreath,  Second  Penn.  Geol.  Survey,  MM,  p.  198. 
'  Report  MM.  19(i.  M3,  p.  .S3. 

*  C.  E.  Hesse,  "The  Paint-Ore  Mines  at  Lehigh  Gap,"    Trans.   Amet 
Inst.  Mm.  Eng.  XIX.,  321. 

"  Report  JIM,  p.  1!)3;  M3,  p.  29. 

»  Report  y\,  p.  (i6;  MM,  p.  194;  M3,  p.  140. 

"•  Report  M3,  p.  43. 

«  Report  M3,  p.  1. 

'  Iron  Manufacturer.'^'  Guide,  p.  650. 

•»  J.  L.  Campbell,  The  Virginias,  July,  1880 

"  The  Virginias,  March,  1880,  p.  35. 

'=  Ibid..  Jaunarj-,  ISHO,  p.  ((. 


1 

.f 

n 
le 
le 

.  5 

' ) 

,  6 

I  • 

in 
ed 
)re 
ili- 
nd 

on- 
ion 
'ur- 
ines 
on 
lin 


o;i 


m 
h 

fed 
iu 

rth 

iiic 


'I 


mer. 


1 

1 

1    \i 

"^ 


5  ''■ 


collec 

^[(lor 

The 

tlie  3I{ 

and  at 

but  Jat 

( )ri.ska 

aij(l   vv( 

for  foil 

brown  J 

weatLei 

dejiosits 

western 

is  know] 

pyn'tes  c 

<Jize(l  ah 

'Sulplmr 

attained 

useful  ni 

beinatites 
'file  iro 

J'"ted  d]\st 

file  State, 

tbc  centivi 

^'le  Kent! 

■''"iitlivvest 

iJiiid,  lm,( 
tlio  ores  ai 
"ear  Owii 
fi'oni  tlje  0 
'■^gion  alFo 

'  B.  S.  Lv 

•^'<Hir,  V;i.. 

1'^.  iSfio  J,   , 


F('I)i 


ii.'irv  ],  s 


rilE  IRON  SERIES  {fN  PART). 


95 


collects  in  the  tunnel  heads  of  the  furnaces  running  on  Low 
Moor  ores,  indicating  the  presence  of  this  metal  in  the  limonite.* 
The  Oriskany  ores  (including  those  referred  hy  Lyman  to 
the  Marcellus)  were  formerly  the  chief  sources  of  Virginia  iron, 
aud  at  Longdale  and  Low  Moor  afforded  very  large  amounts, 
but  lately  the  Siluro-Cambrian  haA'e  taken  precedence.  The 
Orii^kany  ores  yield  from  40  to  4'.i%  Fein  the  furnace  (Pechin), 
and  were  non-Bessemer.  They  have  an  excellent  reputation 
for  foundry  and  mill  work.  Another  prominent  source  of 
bix)wn  hematite  ores  in  Virginia  has  been  of  recent  years  the 
weathered  and  oxidized  upper  portions  of  the  great  pyrites 
dejioi^its  in  Floyd,  Grayson  and  Carroll  counties,  in  the  south- 
western part  of  the  State.  This  belt  extends  over  20  miles,  and 
is  known  as  the  "Great  Gossan  Lead."  Although  uniformly 
pyrites  or  pj-rrhotite  below  the  water  line,  it  is  sufficiently  oxi- 
dized above  to  yield  an  ore  of  about  40  to  41"o  Fe,  with  the 
sulphur  not  much  over  one  per  cent.  The  greatest  depth  is 
attained  where  the  belt  crossses  the  hills.  The  ores  supply  a 
useful  mixture  for  the   neighboring   Siluro-Cambrian  brown 

hematites.'^ 

The  iron  ores  in  Kentucky  are  found  in  three  widely  sepa- 
rated districts,  one  near  Greenup,  in  the  northeastern  corner  of 
the  State,  known  as  the  Hanging  Rock  region ;  the  second  near 
the  cential  part  along  the  Red  and  Kentucky  rivers,  known  as 
the  Kentucky  and  Red  River  region;  and  the  third  in  the 
southwestern  part  near  Lyon  and  Trigg  Counties,  known  as 
the  Cumberland  River  region.  Although  the  first  two  contain 
much  limonite,  it  has  altered  from  nodules  of  carbonate,  and 
the  ores  are  therefore  described  imder  Example  5.  One  locality 
near  Owii.gsville,  in  the  second  region,  has  limonites  altered 
from  the  Clinton  hematite.  (See  Example  <».)  The  Cumberland 
legion  affords  limonites  in  the  Siibcarboniferous.     They  are  in 


'  B.  S.  lA-nian.  "  (icok^y  of  the  IjOw  Moor.  Va.,  Iron  Ores."  Trans. 
Amn:  Iiixf.  Mi)i.  Eihj..  XIV..  SOl.  E.  C.  Means.  "Fine  Dust  at  Low 
Modi',  Vii.."  Trans.  Amrr.  IiLsf.  ^fill.  Eiig..  XVII..  l.'i).  E.  C.  Pechin,  "  Vir- 
;j;inia  Oriskany  Iron  Ores,"  EiKjinvcritHf  and  Miniufj  Journal,  August 
1=^  l^M,  p.  l.-)0;  "Oriskany  Iron  Ores  at  Kicli  Patcli  Mountain,"  Idem^ 
February  1,  8,  and  IT),  1896;  "Iron  Ores  of  Virginia,"  etc.,  Trans.  Amer. 
I»xf.  Min.  EtKj..  XIX..  p.  101(5,  1890. 

'  Iv  ('.  :\Ioxliam,  "Tlie  Oreat  (Jossan  Lead  of  Virginia,"  Trans.  Amer. 
I'lxl.  Min.  Eng.,  XXL,  183,  1892. 


90 


KEMPS  ORE  DEPOSITS. 


rounded  masses,  either  solid  or  hollow,  and  are  distrilnitfd 
through  a  red  clay  along  with  angular  fragments  of  chert.  Tlio 
limonite  pots  are  themselves  filled  with  clay  or  water.' 

2.01.  i;5.  In  Tennessee  the  limonites  of  the  eastern  portion 
come  mostly  under  Example  2«.  In  the  west  they  are  a  south- 
ern extension  of  the  pot-ore  deposits  of  Kentuck}',  and  show  tlie 
same  associated  cliert  and  clay.  Safford  has  called  the  rocks 
containing  them  the  Siliceous  Group.  The  west  Tennessee  dis- 
trict projects  into  Alabama  to  a  small  extent.^ 

2.01.14.  The  principal  limonite  deposits  of  Alabama  come 
under  Example  2rt,  as  do  those  of  western  North  Carolina  and 
Georgia.     Some  limonite  is   produced  in  Ohio,  but  it  is  all 


Fio.  11. — Oeologiccd  Section  of  the  Low  Moor,    Vn.,    Iron-ore  Bed.     After 

B.  S.  Lyinnn,  Tntna.  Amer.  Inst.  Min.  Eng.,  XIV.,  801.     A — 

Marcelliix  Shale;  B — Orixkany  Sainhfone;  C — Lower 

Hdderberg  Limestone;  D — Clinton  Shales. 

weathered  carbonate  and  is  mentioned  under  Example  5. 
Hydrated  ores  are  abundant  in  the  Lake  Superior  region,  but 
are  mentioned  in  connection  with  hematite.  (See  also  2.01.21) 
Deposits  of  brown  hematite  are  worked  in  a  small  way  in  tlie 
southeastern  ])art  of  Missouri,  where  they  rest  upon  Cambrian 
.strata  and  have  a  marked  stalactitic  character.^ 

Limonites  referred  to  the  Cretaceous  by  N.  H.  Wincheil 
occur  in  western  Minnesota.* 

2.01. 15.  The  Annual  Report  of  the  Geological  Sarvey  of 
Arkansas,  Vol.  I.,  consists  of  a  report  by  R.  A.  F.  Penioe 
on  the  "Iron  Deposits  of  Arkansas."  It  at  once  appears  that 
there   is   little  prospect  of  Arkansas  ])roducing   any  notable 


'  W.  B.  Caldwell,  "Report  on  the  Limonite  Ores  of  Trigg,  Lyon,  aud 
Caklwt  11  Counties,"  Kentuvki/  Geol.  Survey,  New  Series,  Vol.  V.,  p.  2.11. 

2  W.  M.  Cliauvenet,  Tenth  Census,  Vol.  XV.,  p.  357;  J.  H.  Safford,  Geol- 
ogy of  Tennessee,  p.  'SV). 

'  P.  N.  Moore,  Oeol.  Survey  of  Missouri,  Repoi-t  for  1874;  F.  L. 
Nason,  Mo.  Geol.  Survey,  1892,  11.,  p.  158. 

*  Bull.  VI.,  Minn.  Geol.  Survey,  p.  151. 


THE  IRON  ShntlHS  (IiV  PART). 


97 


aniounta  of  iron  ore.  Such  deposits  as  have  been  found  are 
priicfcically  all  linionite  (brown  hematite)  and  are  generally 
vt'vy  low  in  iron.  The  ores  occur  in  five  districts,  viz. :  North- 
eastern Arkansas,  northwestern  Arkansas,  the  valley  of  the 
Arkansas  River,  the  Ouachita  Mountains,  and  southern  Arkan- 
sas. They  are  generally  associated  with  sandstones  or  cherty 
limestones.  The  first-named  district  makes  the  best  showing. 
Ill  it  the  ores  are  in  Lower  Silurian  (Calciferous  or  lower) 
sandstones,  cherts  and  limestones.  In  the  second  district  they 
are  in  Lower  Silurian  cherts,  and  Lower  Carboniferous  sand- 
stones. In  the  third  they  occur  with  Carboniferous  and  Lower 
Carboniferous  strata,  but  are  also  in  the  form  of  recent  spring 
(le})osits.  In  the  Ouachita  Mountains  thej'  are  with  Lower 
Silurian  shales  and  novaculites.  In  this  district  the  magne- 
tite or  natural  lodestone  of  ^Magnet  Cove  occurs,  but  it  is  only 
an  interesting  mineral,  and  of  no  practical  importance.  The 
last  district  has  the  ores  in  sands  and  clays  of  the  Eocene,  Its 
continuation  in  Texas  and  Louisiana  is  referred  to  below. 

In  eastern  Texas,  along  the  latitude  of  the  northern  boundar}' 
of  Louisiana,  extended  beds  of  limonite  are  found  capping  the 
mesas  or  near  their  tops,  and  associated  with  glauconitic  sands 
of  Tertiary  age.  They  are  described  by  Penrose*  as  (1)  brown 
laminated  ores,  {'I)  nodular  or  geode  ores,  (;5)  conglom 
erate  ores.  The  first  form  extended  beds  whose  firmness 
has  prevented  the  erosion  of  the  hills,  and  which  are  thought 
to  have  originated  by  the  weathering  of  the  pj-rites  in  the 
greensands  and  from  the  iron  of  the  glauconite  itself.  The 
second  group  occur  just  north  of  the  last,  and  have  probabh' 
resulted  from  the  alteration  of  clay  ironst:one  nodules  (Cf. 
Example  5),  while  the  third  has  formed  in  the  streams  by  the 
erosion  of  the  first  two  and  from  the  smaller  ore-streaks  and 
segregations.  Limonite  also  occurs  in  northwestern  Louis- 
iana." Lawrence  C.  Johnson  has  also  written  of  these  ores,' 
but  the  most  complete  account  has  been  given  by  W.  Ken- 
uedy.*  Mr.  Kennedy  speaks  of  the  available  ores  as  the 
"Laminated   Ores"  and    the   "Nodular   Ores,"   both  belong- 

'  First  Ann.  Rep.  Te.ras  Geol.  Survey,  p.  06;  also  Bull.  Geol.  Soc.  Avier., 
III.  44.  "  Mineml  Resonrces,  1887,  p.  51. 

^  Fiftieth  Concjrrs.'i,  Fir.'it  Session,  Exec.  Doe.  No.  195. 
*  '  Iiou  Ores  of  East  Texan,"  Trans.   Avier.   Inst.  Min.  Eng.,  XXIV., 

-m,  S(52, 


98 


KEMP'S  ORE  DEPOSITS. 


m 


ing,  in  serious  amount,  to  tlie  greensand  beds  of  the  upper 
Eocene.  An  abundant  series  of  analyses  is  given  whicli 
shows  the  ores  to  be  in  general  rather  rich  for  liniou- 
ites,  and  not  high  in  sulphur  or  phosphorus.  Accord- 
ing to  the  grade  of  ore  now  demanded  and  obtained  on 
Lake  Superior,  they  are  seldom  Bessemer  ores,  but  ought  to 
yield  excellent  fouudrj-  irons.  While  the  qiiantity  is  large, 
tlie  situation  precludes  the  use  of  any  fuel  but  charcoal,  and 
the  remoteness  of  markets  will  mostly  restrict  the  output  to 
the  comparatively  limited  local  demand.  The  ore  can  be  won 
b)'  shallow  stripping  or  from  exposed  beds,  up  to  two  feet  or  so 
in  tliickness.  The  geological  relations  of  these  ores  are  inter- 
esting and  important  in  that  the}'  are  derived  from  greensands, 
which  consist  so  largely  of  glauconite,  the  double  silicate  of  iron 
and  potassium,  and  whicii  are  comparatively  deep-sea  deposits. 
The  formation  of  glauconite  by  precipitation  from  sea- water, 
and  as  a  filling  of  the  small  chambers  in  minute  shells  and 
organisms  indicates^  a  marine  method  for  the  concentration  of 
iron  oxide.  It  is  signiticant  that  J.  E.  Spurr  has  lately  advo- 
cated a  similar  source  for  the  ores  of  the  Mesabi  range,  Minn. 
(See  Example  Oe.)  Limonite  is  known  in  a  number  of  locali- 
ties in  Colorado.  The  chief  productive  mines  lie  in  Saguache 
County,  near  Hot  Springs.  They  furnish  a  most  excellent  ore 
from  cavities  in  limestones,  which  are  generally,  but  with  no 
great  certainty,  considered  Lower  Silurian.  R.  Chauvenet 
states  that  the  ores  yield  about  4;5''o  Fe  in  the  furnace.* 

In  Allamakee  County,  in  the  extreme  northeastern  corner 
of  Iowa,  important  deposits  of  rich  limonites  have  been  dis- 
covered on  Iron  Hill  near  the  town  of  Waukon''  and  elsewhere, 

'  On  the  formation  of  greensands,  see  W.  B.  Clark,  Journal  of  Geoloyy. 
II.,  161,  1894. 

-  R.  Cliauvenct.  "Preliminary  Notes  on  the  Iron  Resources  of  Col 
orado,"^ljm.  Rep.  Colo.  State  School  of  Mines,  IHS-l,  p.  21;  "  Iron  Re- 
sources of  Colorado,"  Traus.  Amer.  Inst.  Min.  Eng.,  XVIII.,  20(5.  F.  JI. 
Endlich,  Hayden's  Reports.  187;},  p.  338.  B.  T.  Rutnam,  Tenth  Censit.'^. 
Vol.  XV.,  p.  482.  C.  M.  Rolker,  "Notes  on  Certain  Iron  Ore  Deposits 
in  Colorado,"  Trans.  Amer.  Inst.  Min.  Eng.,  XIV..  206.     Rec. 

•  E.  Orr,  "Brown  Hematite  in  Allamakee  County,  Iowa,"  Amer.  Ot- 
ologist, I.,  129,  1888.  W.  J.  McGee,  "The  Pleistocene  History  of  Northeast 
Iowa,"  Eleventh  Ann.  Rep.  Dir.  U.  S.  Gcol.  Survey,  548,  1891.  Samuel 
Calvin,  "  Geology  of  Allamakee  Co.,"  i^o/n7//  Ann.  Rep.  Geol.  Surv  loim. 
97,  1894.     Rec. 


THE  IRON  SKUIh'S  {fX  PART). 


{)'.) 


The  superficial  decay  of  the  rocks  in  this  luiglaciated  region 
lias  been  extensive  and  has  left  a  thick  mantle  of  residual  mate- 
rial. Calvin  estimates  that  a  total  of  about  800  feet  of  Tren- 
ton and  Galena  lime^^tones,  Matiuekota  shales  and  Niagara 
limestone  have  disappeared,  leaving  behind  them  the  usual 
clays  and  the  iron  ore.  The  latter  is  in  the  form  of  r.odules, 
pipes  and  pots,  and  is  as  much  as  'M)  feet  thick.  It  has  less 
ocher  and  clay  than  is  usual  in  residual  deposits,  and  this  fact, 
together  with  the  amount  of  iron  oxide,  leads  Calvin  to  infer 
more  of  concentration  than  would  result  by  simjile  weathering. 
The  known  chemical  composition  of  the  beds  which  have  dis- 
appeared indicates  that  the  strata  which  were  formerly  over  the 
area  of  the  ore  would  have  furnished  but  a  fraction  of  it. 


Fia.  12. — Ideal  cross-section  of  Iron.  Hill,  near  Waukon,  Allamakee  Co.,  lotca. 

For  explanation  of  letters,  sec  text.     Fourth  Annual  Report 

Iowa  GeoL  Survei/,  p.  101,  1894. 


Professor  Calvin  therefore  suggests,  as  shown  in  the  accom- 
panying figure,  that  a  depression  first  formed,  into  which  the 
iron  oxide  drained  from  a  wide  area.  Having  once  been  con- 
centrated, it  then  settled  down  and  rested  like  a  mantle  upon 
tlie  hilltop,  which  now  stands  in  relief  although  it  represents 
the  rock  formerly  under  the  depression.  In  the  accompanying 
Fig.  12,  A  is  the  St.  Peter's  sandstone;  Bthe  remaining  Tren- 
ton limestone;  the  black  area,  the  present  ore;  CCC  the  origi- 
nal geological  section ;  EE  the  depressed  outline  after  consid- 
erable weathering  and  erosion,  with  the  production  of  the  ore 
at  D.     FF  is  the  present  outline. 

^>Iuch  limonite  occurs  at  Leadville  in  connection  with  the 
lead  silver  ores,  and  is  used  as  a  fiux  by  the  lead  smelters. 
Some  grades  low  in  silver  and  rich  in  manganese  have  even 


i' } 


\. ,  i 


Ill 


I 


100 


KEMP'S  ORE  DEPOSITS. 


been  used  for  spiegel  at  Pueblo.  For  the  geological  relations, 
see  Example  30. 

2.01.10.  Limonites  in  supposed  Carboniferous  limestone 
occur  in  the  East  Tintic  mining  district  in  Utah,  and  seem  to 
be  associated  with  a  decomposed  eruptive  rock,  somewhat  as  at 
Leadville.  The  limonite  is  chiefly  used  as  a  flux  by  lead- 
silver  smelters.' 

2.01.17.  Example  2a.  Silnro- Cambrian  Limonites. — Beds 
of  limonite  in  so-called  hydromica  (talcose,  damourite),  slates 
and  schists,  often  also  with  limestones  of  the  Cambrian  and 
Lower  Silurian  systems  of  the  Appalachians.  The  great  exteut, 
the  geological  relations  and  the  importance  of  these  deposits 
warrant  their  being  grouped  in  a  subtype  by  themselves.  They 
extend  along  the  Appalachians  from  Vermont  to  Alabama,  and 
are  in  the  "Great  Valley,"  as    it  was  early  termed,  which 


8anj  '    J  «        1    Engine  House 


Probably  Limeatona 


Slate 
(Micaceous) 


Limestona 


Fig.  13. — Geological  Section  of  the  Amenia  Mine,  Dutchess  County,  New  York, 

illustrating  a  Silaro-Camhriitn  limonite  deposit.     After  B.  T. 

Putnam,  Tenth  Census,  Vol.  XV.,  p.  133. 

marks  the  trough  between  the  Aichean  on  the  east  and  the  first 
corrugations  of  the  Paleozoic  rocks,  often  metamorphosed,  on 
the  west.  The  masses  of  limonite  are  buried  in  ochreous  clay, 
and  the  whole  often  preserves  the  general  structure  of  the 
schistose  rocks  which  they  have  replaced.  The  original  string- 
ers of  quartz  remain,  following  the  original  folds.  Dolomitic 
limestone  often  forms  one  of  the  walls,  and  still  less  often  (but 
especially  in  New  England)  masses  of  siderite  are  found 
inclosed.  Manganese  is  at  times  present,  and  in  Vermont  is 
of  some  importance  of  itself. 

2.01.18.  The  deposits  begin  in  Vermont,  where  in  the 
vicinity  of  Brandon  they  have  long  been  ground  for  paint. 
A  curious  pocket  of  lignite  occurs  with  them,  and  affords  Ter- 
tiary fossils.  This  prompted  President  Edward  Hitchcock, 
about  1850,  to  refer  all  the  limonites  to  the  Tertiary,  making 

'  B.  T.  Putnam,  Tenth  Census,  Vol.  XV.,  p.  490. 


il 


THE  IRON  8ERIES  {IN  PART). 


101 


an  instructive  example  of  the  occasional  hasty  generalizations 
of  the  early  days.  Lignite  has  also  heeu  found  at  Mont  Alto, 
Pa.  In  northwestern  Massachusetts,  at  Richmond  and  West 
Stockbridge;  and  just  across  the  State  line,  in  Columbia  and 
Dutchess  counties.  New  York,  and  at  Salisbury,  Conn.,  the 
mines  are  large,  and  were  among  the  first  worked  in  the 
United  States.  The  limonito  forms  geodes,  or  "pots,"  pipes, 
stalactitic  masses,  cellular  aggi'egates,  and  smaller  lumps  from 
which  the  barren  clays  and  ochers  are  removed  by  washing. 
The  ore  is  but  a  fraction  of  the  material  mined  and  occurs  in 
irregular  streaks  through  the  clays,  etc.  It  is  mostlj'  obtained 
by  stripping  and  open  cuts,  and  only  rarely  by  underground 
mining,  which  would  present  difficulties  with  such  poor  ma- 
terial for  walls.' 

A  gap  occurs  in  the  succession  of  the  deposits  across  south- 
ern New  York  and  New  Jersey,  although  a  few  minor  ones 
are  known  in  the  western  part  of  the  latter  State,  in  the  mag- 
nesian  limestone  of  tlie  valleys  between  the  hills  of  gneiss.^ 

2.01.19.  In  Lehigh  County  and  to  the  southwest  through 
York  County,  in  eastern  Pennsylvania,  the  limonites  are  again 

'  J.  D.  Dana,  "  Occurrence  and  Origin  of  the  New  York  and  New  Eng- 
land Limonites,"  Amer.  Jour.  Sci.,  iii.,  XIV.,  132.  and  XXVIII.,  398.  Rec. 
E.  Hitchcock,  "Description  of  a  Brown  Coal  Deposit  at  Brandon,  Vt., 
with  an  Attempt  to  Determine  the  Geological  Age  of  the  Principal  Ore 
Beds  of  the  United  States,"  Amer.  Jour.  Set.,  ii.,  XV.,  95;  Hixt.  Geol.  Sur- 
veil  of  Vermont,  I.,  233.  See  also  Lesley,  below.  A.  L.  Holley,  "Notes  on 
the  Sali.sbmy  (Conn. )  Iron  Mines  and  Works,"  Traj/.s.  Amer.  Inst.  Min. 
Eiig.,  VL,  220.  J.  P.  Lesley,  "Mont  Alto  (Pa.)  Lignites,"  Proc.  Amer. 
Aciid.  Sci..  1864,  403-482;  Amer.  Jour.  Sci.,  ii.,  XL.,  119.  L.  Les(jue- 
reux.  "On  the  Fossil  Fruits  Found  in  Connection  witli  the  Lignite  at 
Brandon,  Vt.,"  Amer.  Jour.  Sci.,  ii.,  XXXII.,  ^rM.  H.  Carvill  Lewis, 
"  Tlie  Iron  Ores  of  the  Brandon  Veriod,"  Proc.  Amer.  Ashoc.  Adv.  Sci., 
XXIX.,  427,  1880.  J.  F.  Lewis,  "The  Hematite  (Brown)  Ore  Mines, 
etc.,  Ea.st  of  the  Hudson  River,"  Tian.s.  Ainrr.  In.st.  Min.  Eiig.,  V.,  216. 
J.  G.  Percival,  Rep.  on  the  Geol.  of  Conn.,  p.  132;  also,  Amer.  Jour.  Sci.,  ii., 
II.,  268.  R.  A.  F.  Penrose,  "Report  on  Manganese  Ores,"  Geol.  Siirrei/ 
Ark  ,  1890,  Vol.  I.  (Contains  many  valuable  descriptions  of  Vermont 
limonites.)  B.  T.  Putnam,  Tenth  t'vnms.  Vol.  XV.  C.  U.  Shepherd, 
"Notice,  etc.,  of  the  Iron  Works  of  Salisbury,  Conn.,"  Amer.  Jour.  Sci., 
i.,  XLX.,  311.  J.  C.  Smock,  Bull.  VII  New  York  State  Museum,  pp.  12,  52. 
N.  II.  and  H.  V.  Winchell,  "Taconic  Ores  of  Minnesota  and  Western  New 
England,"  Amer.  Geol,  VI.,  263.     1890. 

■  B.  T.  Putnam,  Tenth  Census,  Vol.  XX.,  p.  1T6.  See  also  Geol.  Survey 
New  Jersey,  1880. 


102 


KEMP'S  OliK  DEPOSITS. 


developed  in  great  amount,  and  run  southwesterly,  with  few 
gaps,  to  Alabama.  It  is  in  this  portion  that  the  "Groat  Val- 
ley" (called  also  the  Cuml)erland  Valley,  or  Valley  of  Vir- 
ginia) is  especially  marked.  Wherever  the  great  limoatono 
formation,  No.  II.  of  Rogers,  is  developed  the  ores  are  found. 
Thia  corresponds  to  the  Calciferous,  Chazy,  and  Trenton  of  New 
York.  Limonites  also  occur  still  lower  in  the  Cambrian  at 
about  the  horizon  of  the  Potsdam  sandstone  or  in  the  over 
lying  slates.  According  to  McCreath,  they  are  divisilile  in 
Pennsylvania  into  ores  at  the  top,  ores  in  the  middle,  and  ores 
at  the  bottom  of  the  great  limestone  No.  II.  Those  at  the  top 
form  the  belt  along  the  central  part  of  the  valley  where  tho 
Trenton  limestone  underlies  the  Utica  or  Hudson  River  slaies. 
Those  in  the  middle  are  connected  with  various  horizons  of  fer- 
ruginous limestones  in  the  Chazy  and  Calciferous.  Those  at 
the  bottom  along  the  north  or  west  part  of  the  South  Mountain- 
Blue  Ridge  range  are  geologically  connected  with  the  Potsdam 
sandstone,  or  the  slates  which  intervene  between  it  and  the 
base  of  the  Calciferous.'  Cobalt  has  been  detected  on  those  of 
Chester  Ridge  by  Boye,  but  it  is  a  rare  and  unique  discovery." 

2.01.!^().  The  Siluro-Cambrian  limonites  run  across  Mary- 
land in  Carroll  and  Frederick  counties,  and  are  mined  to  a  small 
extent.^ 

These  limonites  are  again  strongly  developed  in  the  Shenan- 
doah Vallej'  along  the  western  base  of  the  Blue  Ridge,  and  in 
southwestern  Virginia  in  the  Cripple  Creek  and  New  River 


■  Second  Penn.  Surrey,  Rep.  MM,  p.  199. 

•  Dr.  Boye,  "Oxyd  of  Cobalt  with  the  Brown  Hematite  of  Chester 
Ridge,  Penn.,  Atnrr.  Phil.  Soe.,  Janujiry,  184G.  P.  Fraser,  Second  Grol. 
Swvcy  Penn.,  Reps.  C  and  CC;  "  Origin  of  the  Lower  Sihirian  Limonites 
of  Yoik  and  Adams  Counties,"  Proc.  Avier.  Phil.  Soc,  March.  1875.  See 
also,  'Reniiu-ks  on  a  Paper  of  F.  Prime,"  Tdem,  December  21,  1877,  2or). 
J.  W.  Harden,  "Tlie  Brown  Hematite  Oi'e  Dejwsits  of  South  Mountain 
between  Carlisle,  Waynesborough,  and  the  Southeast  Edge  of  the  Cum- 
berland Valley,"  Trans.  Amer.  Inst.  Min.  Encf.,  I.,  136.  J.  P.  Lesley, 
Sunnnary,  Final  Report,  Vol.  I.,  1893,  pp.  305,  ;$41.  Ree.  A.  S.  McCreatli 
Second  Geol.  Survey  Penn.,  Vol.  MM,  199.  F.  Prime,  Second.  Geol.  Stmnj 
Penn.,  Reps.  D  and  DD;  "On  the  Occurrence  of  the  Brown  Hematite 
Deposits  of  the  Great  Valley,"  Trans.  Amer  Inst.  Min.  Eng.,  IH.,  410; 
Amcr.  Jour.  ScL,  ii.,  IX.,  43:3;  also,  XL,  63,  and  XV.,  361.  Rec.  B.  T. 
Putnam,  Tenth  Census,  Vol.  XV.,  p.  181. 

»  E.  R.  Benton,  Tenth  Census,  Vol.,  XV.,  p.  254. 


mmm 


fc 

1 

K 

i 

iii, 

ii 

1( 


'E.  R 

JHirt  on  tl 
(liiiius,  l-'e 
4;  Munrli 
Iiixt.  Mil, 
"fCfituin 
91 'I ids,'  M 

Pror.   Am 
Ores  of  tl 

EiKjiticcrir 
"Tho  (Jn. 
XXI,,  iri;. 
<'<iiiiity,  V 
"MiniiijT  f, 

'fouviuil,  ,<■' 
iiients,"  7'^ 
f,'iiiia  Knriii 
.'i(!t.    ],.ee. 

Vol.  XV. 


1> 


THE  IRON  HKIUKS  (^/\  IWUT). 


103 


i;<i 


liolt.  The  ores  occur  in  connection  with  calcarooiiH  slwiles,  cnl- 
cHroons  sundstoiKis,  and  inipnrn  linicHtoncs,  Imt  hav<>  not  jiisti- 
liod  the  expectatioiiM  formed  of  tlieni.  'IMit«  geological  ndatioim 
are  Hiniihir  to  tlione  of  the  zinc  ores  descrihed  under  Exainple 
•^(1,  and  the  pictures  of  tlie  zinc  mines  will  answer  for  those 
worked  for  limouite.  In  Carroll  County,  Virginia,  the  gossan 
of  the  great  deposit  of  pyrite  is  dug  for  iron  ore.  The  walls, 
however,  are  older  than  the  Cainhrian.' 

'^.01.21.  The  linionites  of  eastern  Tennessee  are  the  southern 
prolongation  of  the  area  of  southwest  A'irginia.  I'hey  lie 
lietwen  the  Archean  of  the  Unaka  range  on  the  east,  and  the 
Upper  Silurian  strata  in  the  foot  of  the  Cuniherland  tahleland 
()U  the  west.  The  ores  outcrop  in  the  longitudinal  valleys  or 
"coves."  The  hottoms  of  these  valleys,  according  to  SalTord 
(p.  44'.)),  are  f«)rnied  hy  the  shales,  shites,  and  niagnesian  lime- 
stones of  the  Knox  gn)up,  and  in  the  residual  clay  left  by  their 
alteration  the  ore  is  found.  The  gossan  of  the  neigh horing 
veius  of  copper  pyrites,  best  known  at  Ducktown  (see  Example 
!<!),  was  originally  exploited  for  iron.*  The  Tennessee  limon- 
ite  extends  across  northwestern  Georgia,  and  still  farther  east 


'  E.  R.  Benton,  Tenth  Cennus,  Vol.  XV.,  p.  201.  J.  L.  Campbell,  "Re- 
IKjrt  on  tlie  Mineral  ProsjHjcts  of  the  St.  Mary  Iron  ProiHsrty,"  etc. ,  Tlw  Vir- 
ginias, February,  188!},  p.  10.  See  also  The  Vircfinias,  .lamiary,  1880,  p. 
4;  .Marcli,  p.  43.  F.  P.  Dewey,  "Tlie  Ricrh  Hill  Iron  Ores."  Trans.  Ana'i: 
Iiixt.  Min.  Eng.,  X.,  77.  W.  M.  Fontaine,  "  Notes  on  the  Mineral  Deposits 
ofCt'itain  Localities  in  the  Western  Part  of  the  Pine  Ridge,"  The  l'7r- 
(jiiiiitu,  'March,  1883,  p.  44;  April,  p.  55;  May,  j).  73;  June,  p.  92.  B.  8. 
Lyman,  "On  the  Lower  Hilurian  Brown  Hematite  Beds  of  Amerioa," 
Pmi:  Aincr.  Assoc.  Adv.  Sei.,  XVII.,  114.  A.  S.  McCreath.  "Tlie  Iron 
Ores  of  the  Valley  of  Virginia,"  Tnn/.s.  Amer.  Inst.  Min.  Eny.,  XII.,  103; 
EiKjincering  and  Mining  Jonrnal,  .Time,  1883.  p.  834.  E.  C.  Moxhani, 
"The  (Jreat  (iossan  Lead  of  Virginia,"  Trans.  Amer.  Inst.  Min.  Eng., 
XXI.,  in:{.  E.  C.  Pechin,  "The  Iron  Ores  at  Buena  Vishi,  Rockbridge 
C'ounty,  Virginia."  Fhigineering  and  Mining  Journal,  Aug.  3,  188D,  ]).  92; 
"Mming  of  Potsdam  Brown  Ores  in  Virginia."  Engineering  and  Mining 
JouviKd,  Sept.  19.  1891.  p.  337;  "  Iron  Ores  of  Virginia  and  their  Develop- 
ments," Trans.  Amer.  Inst.  Min.  Eng.,  XIX.,  101;  "Ore  Suj)i)ly  for  Vir- 
ginia Furnaces."  Engineering  and  Mining  Journal,  Vol.  LI.,  1891,  pp.  322, 
;54!l.     Rec. 

M.  JI.  Safford.  Geol  of  Te.nn.,  p.  448,  1869.  B.  Willis,  Tenth  Census, 
Vol.  XV..  p.  331.  The  best  works  of  reference  are  the  recent  folios  of  the 
l^.  S.  Geological  Survey,  which  cover  a  large  jKU't  of  southeastern  Ten- 
nessee and  the  neiglil)oring  parts  of  Alabama  and  Georgia. 


ii 


104 


KEMP'S  ORE  DEPOSITS. 


the  so-called  Huronian  limestones  of  North  Carolina  also  enter 
the  State.  But  as  even  these  so-called  Hnronian  schists  and 
associated  marbles  have  been  considered  by  F.  P.  Bradley  to 
be  metamorphosed  Silurian  (Cambrian),  the  ores  may  also  be- 
lonf>;  under  Example  'la.  The  well-determined  Siluio-Cambrifin 
rocks  form  but  a  narrow  belt  of  no  great  importance  in  North 
Carolina.' 

Tl>e  limonites  are  again  strongly  developed  in  Alabama  and 
furnish  a  goodly  proportion  of  the  ore  used  in  tlie  State. 
They  form  a  belt  lying  east  of  the  Clinton  ores  (Example  (>), 
later  described.  As  in  Tennessee,  they  are  associated  with 
strata  of  the  Knox  group," 

2.01,23.  Origin  of  the  Silnro-Camhrian  Limonites.— 
Dr.  Jackson,  of  the  First  Fennsj^lvania  Survey,  argued  in  lS3t)^ 
that  they  originated  in  .situ;  that  is,  by  the  alteration  of  tiie 
rocks  in  and  with  Avhich  they  occur.  Percival,  in  his  report 
on  the  Geology  of  Connecticut  in  1H42  (p.  V-Vi).  attributed  them 
to  the  alteration  of  pyrite  in  the  neighboring  mica-slate. 
Prime,  in  Pennsylvania,  in  1875  and  1S|S  (Reports  D  and 
DD),  considers  that  the  iron  has  been  obtained  b}'  the  leaching 
of  the  neighboring  dolomites  and  slates,  it  being  in  them  either 
as  silicate,  carbonate  or  sulphide;  that  the  ore  has  reached  its 
position  associated  with,  the  slates,  because,  being  imjjervious, 
they  retained  the  ferrugi-^ous  solutions;  and  that  the  potash 
abundantly  present  in  the  slates  probabl}-  assisted  in  precipita- 
ting it.*  Frazer,  in  1876,®  in  studying  the  beds  of  York  and 
Adams  counties,  Pennsylvania,  found  the  hydromica  slates 
filled  with  the  casts  of  pyrite  crystals,  and  held  these  to  have  been 
the  sources  of  the  iron,  because  they  would  afford  ferrous  sul- 
phate and  sulphuric  acid.    The  latter  reacted  on  the  alkali  c'"the 


■  F.  P.  Bradley,  "The  Age  of  the  Clierokoe  County  Rocks,  Nortli  Car- 
oliua,"  Aiiii'i:  Jour.  Sci,  iii.,  IX.,  279,  320;  B.  Willis,  Tenth  Census,  Vol 
XV..  p.  307. 

"  W.  M.  Cliauvenet,  Teiifh  Census.  Vol.  XV.,  p.  383.  H.  MeCalley.  "  Li- 
monites of  Alabama  Geologically  Considered."  Engineering  and  Mining 
Journal,  Dec.  li),  189(5,  W.i.  For  other  refei-euces  to  Alabama  iron  ore 
deposits,  see  under  Exami)le  0.  The  folios  of  the  U.  S.  Geological  Survey 
bearing  on  this  region  should  l)e  consulted. 

»  Ann.  Hep.  First  Pa.  Snrvei/  1839. 

*  Trans.  Amer.  Inst.  Min.  Eng.,  II.  410. 

°  Second  Pa.  Survey,  Rep.  C,  p.  130. 


THE  IRON  SERIES  {fy  P  *  RT). 


105 


I  A 


slates,  producinj^  sodium  sulphate.  This,  meeting  calcium  car- 
bonate afforded  calcium  sulphate  and  sodium  carl)ouate,  which 
latter  precipitated  the  iron.  Calcium  carbonate  alone  is,  how- 
ever,abimdantly  able  to  precipitate  iron  carbonate  and  oxide  from 
both  ferrous  and  ferric  sulphate  solutions  (even  when  neutral) 
without  the  introduction  of  the  alkali,  although  this  might 
account  for  the  alteration  of  the  slab  - 

•101.24.  J.  D.  Dana  has  writtt  .1  at  length  on  the  New 
England  and  New  Vork  deposits,  and  finds  thein  always  at  or 
near  the  junction  of  a  stratum  of  limestone,  proved  in  many 
cases  to  be  ferriferous,  and  sometimes  entirely  siderite,  and  one 
of  hydromica  slate  or  mica  schist.  In  several  mines  bodies  of 
unchanged  spathic  ore  are  embedded  in  the  limonite.  Hence 
Professor  Dana  explains  the  iimonite  as  derived  by  the  weath- 
ermg  of  a  highly  ferruginous  limestone,  from  which  the  limon- 
ite has  been  left  behind  by  the  removal  of  the  more  soluble 
elements,  so  as  practically  to  replace  the  limestone  in  connec- 
tion with  other  less  soluble  matter.  The  limonite  has  also  at 
times  replaced  the  schists,  probably  deriving  its  substance  in 
part  from  iron-bearing  minerals  in  them,  and  changing  these 
rocks  to  the  ochers  and  clays  now  found  with  tha  ores.  These 
views  are  undoubtedly  -^'ery  near  the  truth  for  the  region  stud- 
ied, and  have  been  corroborated  by  observations  of  the  writer. 
(Cf.  also  Example  4.)  Weathering  limestones  do  furnish 
residual  clay,  ocher,  etc.,  as  is  shown  by  the  deposits  of  western 
Kentucky  and  Tennessee  imder  Example  2. 

.'.(11.25.  Another  hypothesis  early  formulated  and  advo- 
cated by  many  is  that  the  limonites  have  been  derived  from  the 
surface  drainage  of  the  old  Appalachian  highlands,  then  have 
been  precipitated  in  still  water  and  have  been  buried  up  where 
tlicv  are  now  found.  A  precipitation  around  the  shores  of  a 
ferruginous  sea  has  also  been  urged  on  the  analogy  of  certain 
exjilanations  of  tlie  Clinton  ore.  (Example  (i.)  Their  supposed 
Tertiary  age  has  already  been  remarked.  All  these  views  are 
esseTitially  hypothetical  and  have  no  good  foundation.^ 

'  See  F.  P.  Dnuningtou,  "Ou  the  Fonnatioii  of  Deposits  of  Sranganese," 
Amrr.  Jour.  ScL,  in.,  XXXVI.,  p.  175.     (Ex],eriinents  10  and  11.) 

'See  II.  D.  Rogers,  Trans.  Asso.  Ainer.  Gcol.  and  Nat.,  lS-12,  p.  345;  E. 
Hitrlicock,  Geol.  Vt.,  Vol.  I.,  p.  'Z'M:  J.  P.  Lesley,  Iron  ManufacturerH' 
(riiiilt.  |).  501;  Rep.  A,  Second  Pa.  Survey,  p.  83;  J.  S.  Newberry, 
Intcrnntional  Review,  November  and  December,  1874. 


t   i 


. 

i.  •: 

!'    : 

I 

.^-■' 

? 

lOG 


KEMP'S  ORE  DEPOSITS. 


ANALYSES    OF   LIMONITES. 


3.01. 2G.  All  published  analyses,  except  when  forming  a 
sufficiently  large  and  continuous  series  from  the  output  of  any 
one  mine,  are  to  be  taken  M'itli  caution.  Ores  necessarily  vary 
much,  and  a  single  analysis  or  a  selected  set  may  give  a  very 
wrong  impression.  The  percentage  in  iron  is  different  for  dif- 
ferent parts  of  the  same  ore  body.  The  few  that  follow  have 
been  selected  to  sliow  the  range  and  the  average.  The  highest 
are  exceptionally  good,  the  lowest  lews  than  the  average,  and  tlio 
medium  values  indicate  approximately  the  general  run. 
Limonites  afford  from  40  to  50%  Fe  as  actually  exploited,  but 
it  is  not  difficult  to  find  individual  analyses  that  run  higher. 
They  are  not,  generally  speaking,  Bessemer  ores. 


ANALYSES  OF   LIMONITES. 


Berksliire  County,  Mass 

Conuecticiit 

Dutohess  County,  New  York . . . 

Rtoten  Island 

Pennsylvania 

Virficinia  (Low  Jloor) 

Tennessee  (Laj^range  Furnace) 

Alahania 

Colorado 

Coloriido,  average 

Prosser  mine,  Oregon 

Pure  mineral 


Fe. 


47.53 
j().48 
4(5.45 
59. 7£ 
5(5. 30 

4;{.;{4 

50. 01 
.50.89 
5:1 157 
4:?.  00 
44.71 
59.92 


0.187 
0.353 
0.370 
0.059 
0.125 
0.(53(5 
0.237 
0.225 
0.034 
0.030 
0.(50(5 


S. 


0.391 
0.020 


0.200 


SiO„ 


14.100 

14.190 

5. 165 


7.900 
20.000 


AlaO, 


8.056 
3.590 


0.700 


H.,  0, 


12.41 


13.00 


14.40 


SIDEKITE  OR   SPATHIC   ORE. 

2,01  27.  Siderite  is  the  protocarbonate  of  iron.  As  a  min- 
eral it  often  contains  mtire  or  less  calcium,  magnesium,  and 
manganese.  When  of  concretionary  structure,  embedded  iu 
shales  and  containing  much  clay,  the  ore  is  called  clay  iron- 
stone. When  the  concretions  enlarge  and  coalesce,  so  as  to 
form  bods  of  limited  extent,  generally  containing  much  bitumi- 
nous matter,  they  are  called  black-band,  and  are  chiefly  devel- 
oped in  connection  with  coal  seams. 

2.01.28.    Example  :).     T/rr//  //oz/.s-Zo^^.— The  nameisapplit'il 
to  isolated  masses  of  concretionary  origin  (kidneys,  balls,  etc.) 


THE  IRON  SERIES  {IN  PART). 


107 


which  may  at  times  coalesce  to  form  beds  of  considerable 
extent.  They  are  usually  distributed  through  shales,  and  on 
the  weathering  of  the  matrix  are  exposed  and  concentrated. 
They  are  especially  characteristic  of  Carboniferous  strata  and 
iliiler  from  black-band  only  in  the  absence  of  bituminous  mat- 
ter and  in  the  consequent  drab  color.  They  weather  to  limon- 
ite,  generally  in  concentric  shells  with  a  core  of  unchanged 
carbonate  within.  Fossil  leaves  or  shells  often  furnish  the 
niK'leiis  for  the  original  concretion,  and  are  thus,  as  at  Mazon 
Creek,  111.,  beautifully  preserved.  When  in  beds  the  ore  is 
sometimes  called  flagstone  ore ;  when  broken  into  rectangular 
masses  by  joints,  it  is  called  block  ore. 

•.'.01, 2;'),  Example  :5a.  Black-hand. — The  name  is  applied 
to  beds  consisting  chiefly  of  carbonate  of  iron  with  more  or  less 
earthy  and  bituminous  matter.  They  are  of  varying  thickness, 
though  rarely  more  than  six  feet,  and  are  almost  invariably 
associated  with  coal  seams.  They  are  tlius  especially  found  in 
the  Carboniferous  system,  and  to  a  far  less  degree  in  the  east- 
ern Jura -Trias.  They  are  also  recorded  with  the  Cretaceous 
coals  of  the  West.  It  is  not  possible  to  separate  the  two  varie- 
ties in  discussing  their  distribution.  The  various  productive 
areas  are  taken  up  geographically,  beginning  with  the  Appa- 
lachian region. 

••i.01.30.  The  carbonate  ores  are  of  great  importance  in  the 
Carboniferous  of  western  Pennsylvania  and  in  the  adjacent 
parts  of  Ohio,  West  Virginia  and  Kentucky.  In  these  States 
the  sy.stem  is  subdivided  in  connection  with  the  coal,  from 
above  downward,  as  follows:  I.  The  Upper  Barren  Measures, 
Permo-Carboniferous,  or  Dunkard's  Creek  Series;  II.  The 
Upper  Productive  Coal  Measures,  or  jVIouongahela  River 
Series;  III.  The  Lower  Barren  Measures,  or  Elk  River  Series; 
IV.  The  Lower  Productive  Coal  Measures,  or  Allegheny 
River  Series;  V.  The  Ci-eat  or  Pottsville  Conglomerate.  In 
the  Upper  Barren  Measures  of  Pennsylvania,  according  to 
McCreath,  there  is  hardly  a  stratum  of  shale  or  sandstone 
^vitllout  clay  ironstone  nodules,  but  no  continuous  beds  are 
known.'  The  deposits  are  not  of  great  actual  imjjortance,  and 
are  worthy  of  only  passing  mention.  In  the  Upper  Productive 
Coiil  Measures  some  ore  occurs  assan'ated  with  the  Waynes- 


ires  some  ore  occurs  assoi;iaieii  wiiti 
^Second  Pa.  Survey,  Rep.  K,  p.  386;  MM.  p. 


159. 


i 

1 

Ill 


I 


108 


KEMP'8  ORE  DEPOSITS. 


burg  coal  seam,  and  again,  just  under  the  Pittsburg  seam, 
there  is  considerable  known  as  the  Pittsburg  Iron  Ore  Group. 
This  latter  ore  becomes  of  great  importance  in  layette  County, 
and  extends  through  several  beds/  The  Lower  Barren  Meas 
urfts  in  Pennsylvania  also  contain  carbonate  ore  in  a  nuniljei 
of  localities.  The  most  persistent  is  the  Johnstown  ore  lied, 
near  the  base  of  the  series.  There  are  two  additional  beds  juwt 
over  the  Mahoning  sandstone. 

The  Lower  Coal  Measures  are  the  chief  ore  producers  in  all 
the  States,     They  furnish  balls  of  clay  ironstone  in  very  mauy 
localities    iu    western    Pennsylvauia,    which    will    be    fouud 
recorded  with  many  additional  references  iu   Report  MM,  p, 
174,  Pa.    Oeol.   Survey.     The  nodules  are  scattered  through 
clay  and  shales.     The  so-called  Ferriferous  limestone,  which 
lies  a  few  feet  below  the  Lower  Kittanning  coal  seam,  affords 
in  its  upper  portion  varying  thicknesses  of  carbonate  ore, known 
as  "buhvstoue  ore,"  which  is  altered  in  large  part  to  limouite. 
Some  little  carbonate  ore  was  found  in  the  early  days  in  the 
anthracite  measures  of  eastern  Pennsylvania.     Several  beds  of 
the  same  occur  m  the  Great  Conglomerate  and  its  underlying' 
(Mauch  Chunk)  shales.     They  are  chiefly  developed  in  south- 
western  Pennsylvania  (Report   KK),  and    may    form    either 
entire   beds  or   disseminated  nodules.     The   limonites  of  the 
Marcellus  stage  that  pass  into  carbonates  in  deptli  in  Perry  and 
the  neighboring  counties  have  alreadj-  been  mentioned  under 
Example  2.     In  West  Virginia  both  Upper  and  Lower  Meas- 
ures afford  the  ore.     From  the  latter  black-band  is  extensively 
mined  on  Davis  Creek,  near  Charleston.^ 

2.01.31.  In  Ohio  a  number  of  nodular  deposits  are  known, 
but  practically  no  ore  is  produced  above  the  ]\Iahoning  sand- 
stone of  the  Lower  Coal  Measures.  Below  this  sandstone  tlie 
ores  are  extensively  developed.  They  extend  up  and  down  llie 
eastern  part  of  the  State,  and  are  both  black- band  and  clay 
ironstone.  Orton  ideutifles  twelve  different  and  well-marked 
horizons  distributed  through  the  Lower  Measures.  He  distin- 
guishes the  stratified  ores,  mostl}'-  black-band,  and  the  Cv/iicre- 


•  Rep.  MM,  p.  162;  KK.  p.  Ill;  L,  p.  98. 

'  M.  F.  Maury  and  W.  M.  Fontaine,  Resources  of  West  Virgimn,  18'?6, 
p.  247. 


tionar' 
ores.' 

2.01, 

tiicky  J 

ing  Ro 

of  the  f 

local  o] 

stone,  1 

to  the  f 

with  th 

tiicky  a 

of  whici 

oils  lim( 

•Un.'S 

the  Dee] 

the  Tria 

A  larj 

from  En 

run  from 

Scatteret 

yard.*^ 

iHeasuret 

associate' 

rado— an 

fi'oni  theil 

source  o: 

l^a.s  recen 

Saud  Cox 

'  Oeol.  oi 

Rook  regioJ 

'  P.  N.  m) 

'  a  Will 

^'ovth  t'aroX 
*  A.  F.  B,| 

-V/'^  Ell  If.. 
'  \V.  1'. 

'  ^-  <  'liaul 
(^olo.  .Sellout 
26(i. 


( 


THE  IRON  SKRIEa  {IN  PART). 


109 


tionary  ores,  includiDg  kidney  ores,  block  oreH,  and  limeatone 
ores. ' 

2.01.32.  The  general  distribution  of  the  iron  ores  of  Ken- 
tucky has  already  been  outlined  under  Example  2.  The  Hang- 
ing Rock  region  is  a  southern  ])rolongation  of  the  Ohio  district 
of  the  same  geological  horizon.  P.  N.  Moore  has  classified  the 
local  ores  as  limestone  ores,  which  are  associated  with  lime- 
stone, block  ores,  and  kidney  ores.  The  last  two  names  refer 
to  the  fracture  or  shape  of  the  masses.  They  occur  associated 
with  the  usual  clay  and  shale.  Farther  west,  between  the  Ken- 
tucky and  Red  rivers,  are  the  other  deposits,  the  principal  one 
of  which  comes  low  in  the  series,  just  over  the  Subcarbonifer- 
ous  limestone.^ 

•2.01.33.  Small  quantities  of  black-band  have  been  found  in 
the  Deep  River  coal  beds,  in  North  Carolina,  associated  with 
the  Triassic  coals.' 

A  large  bed,  or  series  of  beds,  has  recently  been  reported 
from  Enterprise,  Miss.,  in  strata  of  the  Claiborne  stage.  They 
run  from  ten  to  eighteen  feet  in  thickness, and  extend  for  miles.* 
Scattered  nodules  have  been  noted  at  Gay  Head,  Martha's  Vine- 
yard.^ Carbonate  ores  are  as  yet  of  no  importance  in  the  coal 
measures  of  the  Mississippi  Valley.  They  have  been  found 
asf^ociated  with  the  Cretaceous  coals  of  Wyoming  and  Colo- 
rado—and indeed  the  first  pig  iron  of  the  latter  State  was  made 
from  them  in  Boulder  County — but  they  are  not  an  important 
source  of  ore."  An  extended  bed  of  very  excellent  carbonate 
has  recently  been  discovered  with  coal  near  Great  Falls,  in  the 
Saud  Coulee  region  of  Montana.     Being  near  coal,  limestone, 

'  Geol.  of  Ohio,  V.,  p.  378,  and  supplemental  report  on  the  Hanging 
Rock  region  in  Vol.  III. 

^  P.  N.  Moore,  "  On  the  Hanging  Rock  District  in  Kentucky,"  Kentucky 
Oeol.  Survey,  Vol.  I.,  Part  3. 

'  R.  Willis,  Tenth  Census,  Vol.  XV.,  p.  306;  W.  C.  Kerr,  Geology  of 
Xorth  Carol ina,  1875,  p.  225. 

*  A.  F.  Brainanl,  "  Spathic  Ore  at  Enterprise,  Miss.,"  Ti'ans.  Amer.  Inst. 
Mill.  Eiig.,  XIV.,  146. 

'  W.  P.  Blake,  "Notes  on  the  Occurrence  of  Siderite  at  Gay  Head, 
Mass.,"  Trans.  Amer.  In.nt.  J\Iin.  Eng.,  IV.,  112. 

'  K.  Cliiiuvenet,  "Notes  on  tlie  Iron  Resources  of  Colorado,"  Ann.  Rep. 
Colo.  Sehuol  of  Mines,  1885,  188G;  Trans.  Amer.  Inst.  Min.  Eng.,  XVIIL, 

•m. 


110 


KEMP'S  ORK  DEPOSITS. 


and  other  iron  ores,  it  promised  to  be  of  considerable  impor- 
tance.* 

2.01.34.     Example  4.     Burden  Mines,  near  Hudson,  N.  Y. 
Elongated  lenticular  beds  of  clay  ironstone,  passing  into  sub- 


crystalline  siderite,  enclosed  conformably  between  underlying 

slates,  and    overlying    calcareous    sandstone,  of  the    Hudson 

River  stage.     The  ore  occurs  in  four  "basins,"  which  outcrop 

»  O.  C.  Mortson,  Mineral  Eesuurces  U.  S.,  1888,  p.  34. 


ciioiig 


THE  IRON  HE  It  IKS  {IN  PART). 


Ill 


along  the  western  slope  of  a  series  of  moderate  hills,  just  east 
of  the  Hudson  River.     The  hills  have  been  shown  by  Kimball 
to  be  the  eastern  halves  of  anticlinal  folds  now  reduced  by  ero- 
sion to  easterly  dipping  monoclines.     The  western  half  (jf  the 
ore  bodies  has  been  eroded  away,  leaving  an  outcrop  44  feet 
thick  as  a  maximum,  which  pinches  out  along  the  strike  and 
dij).  The  basins  extend  from  southwest  to  northeast,  parallel  to 
the  trend  of  the  hills.    The  beds  are  more  or  less  faulted.     The 
southern  part  of  the  second  basin  affords  Bessemer  ores,  but  the 
others  are  too  high  in  phosphorus.     At  this  point  the  principal 
mining  has  been  done.     According  to  Olmstead,  some  varieties 
are  richer  in  phosphorus  than  others,  but  they  are  so  intimately 
mixed  as  not  to  be  practicably   separated.     Up  to   1S81)  the 
mines  had  produced  4r»(),0()()  tons  of  roasted  Bessemer  ores. 

".'.(11.35.     In  their  geological  relations  the  ores   are   of  the 
greatest  interest,  as  they  occur  in  the  western   limit   of  the 
nietamorphie  belt,  which  forms  the  basis  of  the  Taconic  con- 
troversy, 3'et  in  strata  which  have  been  identified  by  fossils. 
Beilsof  limouite  hitherto  regarded  as  Siluro  Cambrian  occur  to 
the  east;  and   should  further   study,  on   the    lines  developed 
chiefly    by    J.  D.  Dana,  W.  B.  Dwight,  and    C.  D.  Walcott, 
clear  up  their  stratigraphical  relations,  the  work  done  in  devel- 
oping the  structure  of  the  siderite  basins,  as  pointed  out  by 
Kimball,  may   be   of   great  aid    in   explaining    them.     Very 
similar  bodies  of  siderite  occur  with  these  limouites.     (Exam- 
ple 'la.)     The   Burden  ores  are  relativel}' liigh    in    magnesia, 
and  this  leads  Kimball  to  suggest  their  original  deposition 
from  the  off-shore  drainage  of  the  basic  rocks  of  tl)e  Archean 
highlands.     Further,  it  may  be  added  that  the  ores  in  their 
k'utieular  shape  are  highly  suggestive  of  a  possible  origin  for 
magnetite  deposits,  and  they  are  again  referred  to  under  "]\Iag- 
netite."     Other  deposits  of  siderite  in  the  shales  of  the  Marcel- 
Ins  stage  are  known  and  were  formerlv  worked  at  Wawar- 
airig.  Ulster  County,  across  the  Hudson  River.* 

'  J.  P.  Kimball,  "Siderite  Basins  of  the  Hudson  River  Epoch,"  Amcr. 
Jour.  Sri.,  III.,  xl.  155.  I.  Olmstead,  "Distribution  of  Phosphorus  in  the 
Hiiilson  River  Carbonate,"  Trans.  Amer.  Inst.  Min.  Eng.,  XVIII.,  852.  R. 
W.  Kaymond,  "The  Spathic  Ores  of  the  Hudson  River,"  Trans.  Amcr.  Inst. 
^in.  Emj.,  IV.,  309.  J.  C.  Smock,  Bulletin  VIL  of  Neio  York  State  Mns- 
eum  on  Iron  Ores,  p.  63. 


i;  !      !      ', 


iia 


KEMPH  ORE  DEPOSITS. 


2.01.36.  Example  f).  Roxbury,  Conn.  A  fissure  vein  in 
gneiss,  six  to  eight  feet  wide,  of  crystalline  8itierite,with  which 
are  asociated  (juartz  and  a  variety  of  metallic  sulphides, 
galena,  chalcopyrite,  zinc  blende,  etc.  Although  productive  in 
former  years,  it  is  no  longer  worked,  and  is  of  scientific  more 
than  economic  interest,  being  a  unique  deposit.  It  has  fur- 
nished many  fine  cabinet  specimens.* 

2.01.37.  The  spathic  ores  are  the  lowest  in  iron  of  all,  and 
in  the  raw  state  are  often,  if  not  always,  far  below  the  limit 
of  profitable  treatment.  Calcination,  however,  drives  off  tJio 
carbonic  acid  and  moisture  and  brings  the  percentage  of  iron  \\\) 
to  a  merchantable  grade.  The  later  development  of  the  iron 
indus':ry  in  this  country  has  been  unfavorable  to  spathic  ores, 
and  3'ear  by  j'ear  their  amount  has  decreased  until  now  it  is 
nearly  obliterated,  being  only  about  one  per  cent,  of  the  total. 

2.01.138.  The  subjects  of  limonite  and  siderite  cannot  well 
be  passed  without  further  reference  to  their  genetic  relations  as 
connected  with  limestone.  The  processes  involved  concern  not 
alone  these  ores,  but  also  the  more  metamorphic  forms — hema- 
tite and  magnetite — into  which  they  may  pass  by  reason  of 
subsequent  changes.  It  was  stated  earlier  (2.01.05)  that  cal- 
cium carbonate  precipitated  from  ferric  salts,  ferric  hydrate,  and 
from  ferrous  salts,  ferrous  carbonate,  which  in  the  presence  of 
oxygen  quickly  changed  to  ferric  hydrate.  J.  P.  Kimball"  has 
recently  added  a  note  on  the  chemistry  of  the  process  which 
modifies  it  somewhat.  He  brings  out  the  fact  that  it  is  tlie 
hydrous  carbonate  of  iron  which  is  precipitated  from  ferrugi- 
nous salts  by  the  various  alkaline  carbonates,  and  that,  l)eing 
an  unstable  salt,  it  quickly  oxidizes  to  a  hydrous  oxide.  From 
this  the  argument  is  made  that  bodies  of  siderite,  or  anhydrous 
ferrous  carbonate,  could  not  have  originated  by  direct  precipi- 
tation, but  must  have  done  so  by  pseudomorphous  replacement 
of  limestone.  Dr.  Kimball  then  follows  out  the  possible  meta- 
morphism  or  changes  of  these  bodies  to  other  forms  of  iron  ore, 


'  J.  P.  Lesley,  Iron  Ma7iufacturers'  Guide,  p.  649.  C  U.  Shejiliei'il. 
"Report  on  the  (neology  of  Connecticut,"  1837,  p.  30,  Anier.  Jour.  Sci.,  I., 
xix.  311. 

'  J.  P.  Kimball,  "Gene.sis  of  Iron  ores  by  Lsoinorphous  and  Pseudomor 
phous  Replacement  of  Limestone,"  Amer.  Jour.  Sci.,  September,  1^91,  ]< 
231,  and  conclusion  in  the  ^4/»('r.  Geol.,  December,  1891. 


THE  IRON  SKIilh'S  (IN  PART). 


113 


citing,  however,  among  many  that  are  imexceptionable,  some 
iiistanceH  as  posHihle  examples  for  which  the  field  relations  give 
hut  sliglit  justification.  The  specular  ores  with  the  porphyries 
of  Missouri  are  of  this  latter  character,  and  the  work  of  C  H. 
Smyth,  Jr.,  later  cited,  on  the  o()litic  Clinton  hematites  gives 
strong  ground  for  thinking  them  accumulations  in  shallov 
waters  as  concentric  layers  upon  original  nuclei  of  quartz. 

2.01. J3S>.  While  the  importance  of  limestone  as  a  cause  of 
the  formation  of  bodies  of  iron  ore  cannot  he  too  highly  empha- 
sized, and  it  is  (piite  possible  that  some  puzzling  ones,  such  as 
many  magnetite  beds,  have  originated  in  this  way,  and  that 
the  limestone  has  so  entirely  disappeared  as  to  give  slight  clue 
to  its  original  presence;  yet  it  must  not  be  overlooked  that 
siderite  often  does  form  in  nature  quite  independently  of  cal- 
cite,  and  that  conditions  must  be  often  such  as  to  make  this 
possible.  If  vuggs  with  free  crystals,  or  if  cleavage  masses 
with  the  proper  angle  occur  in  a  deposit,  we  must  admit  that 
the  siderite  is  produced  under  circumstances  not  different  from 
those  which  prevailed  during  the  formation  of  the  walls  or  of 
the  massive  mineral.  Repeated  experience  indicates  that  these 
are  not  extraordinary. 


;i    n 


'f 


CHAPTER  II. 

THE  IKON  SERIES  CONTINUED— HEMATITE,  RED  AND  RPECULAH, 

2.02.01.  The  seaquioxide  of  iron,  FaOs,  is  always  of  a  red 
color  when  in  powder.  If  it  is  of  earthy  texture,  this  color 
shows  in  the  mass,  and  the  ore  is  called  red  hematite;  if  the 
ore  is  crystallized,  the  red  color  is  not  apparent,  and  the  hril- 
liant  luster  of  the  mineral  gives  it  the  name  specular  hematite. 
The  red  hematites  are  first  treated. 

3.02.03.  Example  0.  Clinton  Ore. — Wherever  the  Clinton 
stage  of  the  Upper  Silurian  outcrops,  it  almost  invariably  con- 
tains one  or  more  beds  of  red  hematite,  interstratified  with  the 
shales  and  limestones.  These  ores  are  of  extraordinary  persist- 
ence, as  they  outcrop  in  Wisconsin,  Ohio  and  Kentucky  in  the 
interior,  and  then  beginning  in  New  York,  south  of  Lake 
Ontario,  they  nm  easterly  across  the  State.  Again  in  Penn- 
sylvania they  follow  the  waves  of  the  Appalachian  folds  and 
extend  south  into  West  Virginia  and  Virginia  in  great 
strength.  They  are  found  in  eastern  Tennessee  and  northwest- 
ern Georgia,  and  finally  in  Alabama  are  of  exceptional  size 
and  importance.  The  structure  of  the  ore  varies  somewhat. 
At  times  it  is  a  replacement  of  fossils,  such  as  crinoid  stems, 
inolluscan  remains,  etc.  (fossil  ore);  again  as  small  oolitic  con- 
cretions, like  ilaxseed  (flaxseed  ore,  oolitic  ore,  lenticular  ore); 
while  elsewhere  it  is  known  as  dyestone  ore.  The  ore  in  many 
places  is  really  a  highly  ferruginous  limestone,  and  below  the 
water  level  in  the  unaltered  portion  it  often  passes  into  lime- 
stone, while  along  the  outcrop  it  is  quite  rich. 

2.03.0-}.  In  Dodge  County,  southeastern  Wisconsin,  the  ore 
in  14  to  26  feet  thick,  and  consists  of  an  aggregate  of  small 
lenticular  grains.*    In  Ohio  it  outcrops  in  Clinton,  Highland 

'  T.  C.  Chamberlin,  Grol.  Survey  Win.,  Vol.  I.,  p.  170.  R.  D.  Irving, 
"  Mineral  Re.sources  of  Wisconsin,"  Trann.  Ainer.  Inst.  Mui.  Emj.,  VIII. 
478;  Geol.  Survey  Wis.,  Vol.  I.,  p.  625. 


THE  IRON  SEItlEH  CONTINUED. 


115 


and  Adams  conntios,  in  the  Boutb western  portion  of  the  State 
ivlong  the  Hanks  of  the  Cincinnati  Arch,  but  it  in  thin  and  poor 
in  iron,  although  ridi  in  fossils.*  A  small  area  of  the  Clinton 
lias  furnlslied  considerable  ore  in  Bath  County,  Kentucky, 
where  it  is  altered  to  limonite." 

2.02.04.  Coming  eastward,  the  limestones  and  the  shales  of 
the  Clinton  outcrop  in  the  Niagara  River  gorge  in  Now  Vork, 
but  show  no  ore.  This  appears  first  in  (piantity  in  Wayne 
County,  a  himdred  miles  east  and  just  south  of  Lake  Ontario. 
Que  bed  reaches  20  to  22  inches.     Farther  east  are  the  Sterling 


iilioi 


— r  Limestone  0-6 

1 

i^  Ore  2' 

—  _  Shale? 

.  FlQ.  i6.—CHntoii  Ore,  Ontario,  mn/ne  Count i/,  New  York.     After 

C.  II.  Smytii,  Jr. 

mines,  in  Cayuga  County ;  and  again  near  Utica,  in  the  town  of 
Clinton,  which  first  gave  the  ore  its  name,  it  is  of  great  eco- 
uomic  importance.  There  are  two  workable  beds,  the  upper 
of  which,  with  a  thickness  of  about  two  feet,  is  the  only  one 
now  exploited.  Beneath  this  are  12  or  15  inches  of  shale,  and 
then  the  second  bed  of  8  inches  of  ore.^  Some  25  feet  over  the 
iippor  bed  is  still  a  third,  which  is  too  low  grade  for  mining. 
It  is  four  to  six  feet  thick,  and  is  locally  called  red  llux.  It 
consists  of  p«bbles  and  irregular  fragmcMits  of  fossils,  which 
are  coated  with  hematite  and  cemented  with  calcite. 


'  J.  S.  Newberry,  Geol.  of  Ohio,  Vol.  III.,  p.  7.     E.  Orton,  Geol.  of  Ohio, 
Vol.  v..  p.  371. 

'  N.  S.  Shaler,  Geol.  of  Kif.,  Vol  III.,  163. 
■   '  A,  II,  Chester,  "The  Iron  Region  of  Central  New  York,"  address  be- 
fore the  Utica  Merchants  and  Manufacturers'  Association,    Utica,  1881. 
JO.  Smock,  Bull.    VII.  of  N.    Y.  State  Museum,  June  188!).     C.  H. 
Smyth,  Jr.,  "On  the  Clinton  Iron  Ore,"  Avier.  Jour.  Sci.,  June,  1893,  p 
487.     Zuitsehr.  fur pntkt.  Geuloyie,  1894,  304. 


r 


116 


KKMVa  OltE  DEPOSITS. 


2.03.05.  The  rockH  of  tho  Clinton  tlii(!ken  greatly  in  Peuu- 
Bylvaniu  and  run  HoutlnveHtward  through  the  central  ])art  of 
tho  State.  Six  tlittVront  ore  IhmIh  have  heen  recognized,  of  which 
the  lower  are  probably  eijuivalent  to  the  southern  dyestone 


ores. 


TT 


a,    .  .,■  i|i  III. I  I  I 


Caloareoua  Sandstorm 

and  I 

thin  Shale  layers    PO-h 


Non-Oolitio  Ore    I 
(Red  Flux)      0 


H3BraBKS9t&.V 


Calcareous 
Sandstone 


Blue  Shale 

and  thin  . 

Sandstone  layer!  IQr 


Oolitio  Ore  2 

Shale    2'      , 
Oolitic  Orel 

Blue  Shale 

and  thin  , 

Sandstone  layers  100  X 


Fig.  n.— Clinton  Ore,  Viinton,  New  York.     After  0.  II.  Smyth,  Jr. 

The  ores  are  of  chief  importance  in  the  Juniata  district. 
The  belt  extends  south  westward  acros3  Maryland  and  eaHteiD 
West  Virginia,  where  the  beds  are  quite  thick,  although  as  yet 
not  much  developed,  and  appears  in  the  extreme  southwest 
corner  of  Virginia.  Tlience  it  runs  across  eastern  Tennessee, 
arJ  is  of  very  great  importance.     The  lines  of  outcrop  are 

•  J.  H.  Dewees,  "  Fossil  Ores  of  the  Juuiata  Vallpy,"  Penn.  Geol.  Sur- 
vey, Rep.  F.  E.  d'luvilliers,  Ibid.,  Rep.  F;j  (Uuion,  Snyder,  Mifflin,  and 
J'miata  counties).  A.  8.  McCreath,  Ibid.,  Rep.  MM,  p.  231.  J.  J. 
Stevenson,  Ibid.,  Keps.  MM  and  T3  (Bedford  and  Fulton  counties).  !■ 
C.  White,  Ibid.,  Reps.  MM  and  T;J  (Huntingdon  County) .  H.  H.  Stock, 
"  Ores  at  Danville,  Montour  County,"  'Trans.  Amer.  Inst.  Min.  En(j.,XX.> 
869. 


rilK  lltON  SKIifKS  CONTTNUED, 


117 


known  aa  'Myestouo  ranges."  They  lie  went  of  tlio  Siluro-Cani- 
hriiin  limestones  (Example  'Z(()  and  in  the  edges  of  the  Cum- 
litwland  tableland.  Four  or  five  are  known,  of  which  the 
largest  extends  across  the  State.     This  ore  is  more  foHsiliferous 


wmm 


Fio.  \9.— Clinton  Ore,  Eureka  Mine,  Oxmoor,  Ala.     After  C.  II.  Smyth,  Jr. 

toAvard  the  sonth  and  more  oiilitic  toward  the  north.   It  is   very 
productive  in  the  Chattanooga  region.' 

Ji.Oii.OO.     The  Clinton  jnst  ajjpears  in  northwestern  Georgia, 
and  continues  thence  into  Alabama,  where  it  is  again  of  great 


Fig.  19. — Cross-section  of  the  Sloss  Mine,  Red  Mountain,  Ale. 

importance,  and,  with  the  less  productive  Siluro-Cambrian 
liinoiiitos,  furnishes  practically  all  the  ore  of  the  State.  The 
outt'njp  can  l)e  traced  almost  continuously'  for  \'M)  miles.  The 
ore  is  rich  in  fossils  and  occurs  in  several  beds,  which,  although 
averaging  much  less,  may  aggregate,  as  at  the  Eureka  furnace, 
as  much  as  ;54  to  '.u  feet.     The  chief  mines  are  in  Red  Mountain, 

'  Killehrew  and  Safford,  Resources  of  Tennessee.  E.  C.  Pechin.  "The 
Irou  Ores  of  Virginia,"  etc.,  Trans.  Anier.  In.'it.  Min.  En<j.,  XIX.,  lOlfi. 
J.  B.  Porter,  "Iron  Ores,  Coal,  etc.,  in  Alabama,  Georgia,  and  Tennessee," 
Tranii.  Amer.  Inst.  Min.  Eng.,  XV.,  170.  J.  M.  Safford,  Geol.  of  Tcnn. 
P.  N.  Moore,  Virginias,  May,  1880,  p.  78. 


--    i 


118 


KEMP'S  ORE  DEPOSITS. 


a  local  name  for  the  northeast  and  southwest  ridges,  in  which 
the  ore  outcrops,  east  and  south  of  Birniiugham.  Folds  aud 
faults  have  brought  the  beds  into  close  proximity  with  the  coal 
aud  limestone  of  the  region,  aud  thus  iuto  a  position  very 
favorable  for  economic  working.' 

The  accompanying  map,  Fig.  -.'O.  illustrates  the  geography 
and  economic  geology  of  the  Birminghaiu  district.     lu  expla- 
nation it  may  be  said  that  the  three  coal  fields,  ibo  Warrior, 
the  Cahaba,  and  the  Coosa,  make  three  elevated  basins,  formed 
in  part  by  synclinal  foldings  aud  in  part  by  faulting.     The 
intervening  strips  are  relatively  de[)ressed   aud  constitute  the 
so-called  valleys,  each  of  which  has  its  own  name.     Thus  there 
is  a  long  valley  in  which  Birmingham  is  situated  aud  which 
forks  at  the  northeast  corner  of  the  map.     The  central  portion 
of  it  consists  of  Cambrian  and  Lower  Silurian  rocks,  which 
yield  brown  hematite  ores,  as  indicated  on  the  map.     Tliey, 
however,   are  a    miner  feature  aud   do  not  form  t)ver   Ki'V 
of  the  total  furnace  supply.     On  each  side  of  the  valley  tliere 
is  a  ridgo  called  Red    Mountain,  mostly  formed   by  Clintou 
strata,  with   Trenton  limestone  beneath  and   black   Devonian 
shale  above.     The  Clinton  reaches  a  thickness  of  150  feet,  but 
is  quite  variable  in  character.     It  may  contain  as  many  as  five 
or  more  beds  of  ore  of  differing  thicknesses  aud  somewlint  con- 
trasted  composition  and    structure.     The   best    of    these  are 
worked.     The  Clinton  beds  in  Red  Mountain  dip  on  each  side 
awaj'  from  the  center  of  the  valley,  and  really  are  the  remains 
of  an  anticline  eroded  at  its  crest.  The  anticline  is  of  the  usual 
Ajjpalachian  type  with  steeper  dips  on  one  flank,  in  this  cuho 
the  northwestern,  than  on  the  other,  and  the  crest  is  nearer  the 
northwest  side  than  the  northeast,     Tlje  dip  at  one  important 
miue  is  shown  in  Fig.  is.     The  most  productive  points  are  oast 
and  south   of  Birmingham,  aud   along  this   line   the   largest 
mines  are  situated.     The  ore  is  chiefly  won  by  open  cuts,  ami 
is  laid  bare  by  stripping  off  the  hanging.     Curiously  enough, 

'  A.  F.  Brainerd,  "On  the  Iron  Ores,  Fuels,  etc.,  of  fiinniiip:hain,  Ala," 
Trans.  Ainrr.  Iiisf.  Min.  Emj.,  XVII.,  151.  "TlieSlo.ss  Iron  Ore  Mines," 
Engineering  and  Mining  Juunial,  Oct.  1,  1893,  p.  3IH.  T.  S.  Hunt,  "Coal 
and  Iron  in  Alabama,"  TrmiH.  Atner.  Inst.  Min.  Eiig.,  XI.,  23(5.  J.  B. 
Porter,  "Iron  Ores,  Coal,  ftcv,  in  Alabama,  Georgia,  andTenne.ssee,"  Trans. 
Amer.  Inst.  Min.  Eng.,  XV.,  Ki).  E.  A.  Smith,  Alabama  Geol.  Swrvey, 
1876;  also  Proc.  Amer.  Ahsoc.  Adv.  Sci..  XXVII.,  246. 


V 


Vi.„. 


l-'ii..  'JO^ 


TUE  IRON  SERIES  CONTINUED. 


110 


Y\r,.  'i<i\.—  M(tp  uf  tin   Vin'iiiti/ of  liinidtKjlKnn,  Ala.     From  the   7'rans(trtions 
1)1' the  Aiiuricaii,  Inditutc  vf  Miaimj  Enyincera,  Vol.  XIX.,  Plate  IV. 


I 


120 


KEMP'S  ORE  BEPOSirS. 


for  an  ore  in  the  midst  of  limestone  and  limey  shales,  it  is  pre- 
vailingly siliceous,  so  that  non-siliceous  or  calcareous  varieties 
are  much-sought-for  mixtures.  The  red  hematites  are  also 
exposed  in  Murphrees  V^alley  and  are  developed  in  some  large 
and  productive  openings.  While  on  the  west  this  valley  has 
the  normal  and  anticliual  flank,  it  is  faulted  along  the  east  so 
that  the  Clinton  measures  lie  against  the  Cambrian  shales  and 
are  overthrown  to  a  steep  northwesterly  dip. 

2.0*^.07.  Red  hematite,  supposed  to  bo  of  the  Clinton  stage, 
occurs  in  Nova  Scotia  in  very  considerable  amount,  in  Pictou 
and  Antigonish  counties.' 

2.02.08.  In  general  the  Clinton  ore  is  characterized  by  a 
high  percentage  of  phosphorus,  and  is  seldom,  if  ever,  available 
for  Bessemer  pig.  It  is  chietlj'  employed  for  ordinary  foundry 
irons.  The  percentage  in  iron  varies  nuich.  Experience  at 
Clinton,  N.  Y..  shows  that  it  averages  about  44  "o  Fe  in  the  fur- 
nace. These  hematites  have  undoubtedly  originated  in  some 
cases  by  the  weathering  of  ferruginous  limestones  above  the 
water  level.  I.  C.  Russell  has  shown  that  the  unaltered  lime- 
stones at  the  bottom  of  a  mine  in  Alalia.  Ala.,  250  feet  from 
the  surface,  contained  but  7.7/')"o  Fe,  while  the  outcrop  afforded 
57.52**0.  J.  B,  Porter  has  recorded  the  gradual  increase  of 
lime  also  in  another  Alabama  mine  from  a  trace  at  the  outcrop 
to  30.55%"  at  135  feet.  Other  writers  have  explained  these  beds 
as  due  to  the  bringing  of  iron  in  solution  into  the  sea  of  the 
Clinton  age  and  to  its  deposition  as  small  nodules,  etc.,  or  as 
ferruginous  nnul  (Roger,  Lesley.  Newl)erry).  In  this  way 
an  oolitic  mass  has  originated,  as  in  the  modern  Swedish  lakes 
(Newberry).  (See  Example  1.)  N.  S.  Shaler  has  argued,  on  the 
basis  of  the  Kentucky  beds,  that  the  iron  has  been  derived 
from  the  overlying  shales,  and  descending  in  solution  has  been 
precipitated  by  the  lower-lying  limestones.  As  the  shales  are 
themselves  calcareous,  this  seems  im[)rohable.  A.  F.  Foerste 
has  shown  that  the  ore  is  ver}'  often  deposited  either  in  the 
interstices  of  fragments  of  bryozoans  or  as  replacing  thei\  sub- 
stance. The  rounded,  witer-worn  character  of  the  original 
fragments  is  regarded  as  occasioning  the  apparent  concretion- 
ary character.     Admirable  work  upon  the  origin  of  the  ore  has 


•  8ir  J.  VV.   Dawson,   Acadian  Oeoloijij,   p.   5')1. 
Survc'i/,  18815. 


Fletcher,   Can.   (Jtvl. 


rut:  IRON  SERIES  CONTINUED. 


\%\ 


also  been  doue  by  C.  H.  Smyth,  Jr.  He  finds  that  the  small 
oolites,  or  concretions,  as  they  occur  at  Clinton,  N.  Y.,  and 
many  other  localities,  have  a  water- worn  grain  of  quartz  as  a 
nucleus.  The  character  of  the  grain  is  such  that  it  has  evi- 
dently been  derived  from  granitoid  or  schistose  rocks.  Tlie 
hematite  comes  off  at  times  in  concentric  layers,  when  tapped 
gently.  It  may  also  be  dissolved  away  so  as  to  leave  a  sili- 
ceous cast  or  skeleton  of  the  spherule.  Dr.  Smyth  thus  makes 
H  strong  argument  that  the  ores  in  such  cases  are  concretion- 
ary, and  that  they  were  formed  in  shallow  waters  around  the 
nuclei  of  sand.  But  he  also  admits,  as  others  jjoted  above 
have  indicated,  that  the  replacement  of  brj'ozoa  and  the  weath- 
ering of  ferruginous  limestone  have  in  many  localities  played 
their  part.  The  iron  ore  is  in  the  latter  case  a  residual  prod- 
uct, but  now  the  mine  waters  are  depositing  calcium  carbonate 
rather  than  removing  it.' 

2.02.09.  Glenmore  Estate,  Greenbrier  County,  West  Vir- 
ginia. A  bed  of  red  hematite  in  Oriskany  sandstones.  Limon- 
ites  are  "ibundant  in  the  Oriskany  of  Virginia,  and  the  hema- 
tite may  have  been  derived  from  some  such  original." 

2.02.10.  Mansfield  Ores,  Tioga  County,  Pennsylvania. 
Three  beds  of  ore  are  found  in  the  strata  of  the  Chemung  stage 
of  Tioga  County,  Pennsylvania.  They  are  known  as  (1)  tlie 
Upper  or  Spirifer  Bed,  (2)  the  Middle  or  Fish  Bed,  and  (:J)  the 
Lower  Ore  Bed.  No.  1  is  full  of  shells  and  is  about  2(i(>  foet 
below  the  Catskill  red  sandstones,  and  at  Mansfield  is  two  to 
three  feet  thick.  No.  2  is  oolitic,  resembles  the  Clinton  ore, 
aud  affords  fish  remains.     It  lies  about  200  feet  below  No.  I 


'  A.  Y,  Foerste.  "  Clinton  Group  Fossils,  with  Special  Reference  to  Col- 
leL'tioiis  from  Indiana,  Teiniessee,  and  CJenrt^ia,"  Amer.  .hmr.  Sci.,  iii., 
XL. '..'o^.  (Abstract;  original  not  cited)  "Clinton  Oolitic  Iron  Ores," 
Ami:  Jour.  Sci..  iii.,  XLl.,  2S.  Rec.  "Notes  on  Clinton  (iroup  Fossils, 
with  Special  Reference  to  Collections  from  Maryland,  Tennessee,  and 
•i^or^ia, "Pcoc.  Host.  Soc.  Nat.  Ili.'^t..  XXIV.,  'HV,].  J.  V.  Lesley,  Iron  Man- 
nfavtarers'  Guide,  p.  (ill.  J.  S.  Newberry,  "(ienesis  of  the  Ores  of  Iron," 
School  of  Mines  Quarierly,  November,  tS80,  p.  153.  Rec.  H.  D.  Rogers, 
':;«<./.  0/  Penn.,  Vol.  TI.,  p.  137.  N.  S.  Shaler,  Gcol.  of  Kij.,  Vol.  III.,  p. 
'•>i  C.  U.  Smyth,  Jr.,  "On  the  Clinton  Iron  Ore,"  .^IwtT.  Jour.  Sci., 
.hine,  lHi)2,  p.  487.  Rec.  "  Die  Haematite  von  Clinton  in  den  oestlichen 
VtTfiiiij^ten  Stachiii,"  Zeitsrher.  fin-  imikt.  (IvoIiHiie.  IS'M.  ;!(I4. 

'  VV.  X.  Page,  "Tlie  (Jleinnore  Iron  Estate,  (ireeubrier  County,  West 
Virginia,"  Trans.  Auier.  Inst.  Min.  Eng.,  XVII.,  ll."). 


122 


KEMP'S  ORE  DEPOSITS. 


and  varies  up  to  six  or  seven  feet  thick.  No.  3  is  100  to  ^00 
feet  lower,  and  contains  small  (juartz  pebbles/  The  ore  is  not 
rich,  and  but  little  has  been  mined.  It  is  a  brownish  red  hema- 
tite.'' 

2.02.11.  Beds  of  red  hematite  are  reported  by  Schmidt  in 
the  Lower  Carboniferous  of  western  central  Missouri,^ 

3.02.12.  Example  7.  Crawford  County,  Missouri.  Bodies 
of  finely  crystalline  specular  hematite,  associated  witl 
chert,  sandstone  fragments,  residual  clays  and  some  pyrite 
in  conical  or  rudely  cylindrical  depressions  in  the  Cambrian 
(Ozark)  Series.  A  broad  area  of  upheaval  runs  across 
central  Missouri  from  the  east,  near  St.  Louis,  to  the  south- 
western part  of  the  State.  In  the  eastern  and  central  })ortious 
it  is  chiefly  composed  of  Cambrian  and  Silurian  strata,  but  to 
the  southwest  Lower  Carboniferous  come  in  (see  2.0G,0()).  The 
hematites  here  considered  belong  in  the  Cambrian.  In  the 
region  of  the  mines  there  is  a  lieavy  sandstone  stratum,  earlier 
called  the  "Second  Sandstone,"  but  in  tlie  later  reports  described 
as  the  Rouhidoux.  It  is  underlain  by  a  lieavj'  limestone  stra- 
tum locally  called  tlie  G  asconade.  The  Ozark  uplift  was  formed 
at  the  close  of  the  Lower  Carboniferous  and  has  remained  exposed 
to  atmospheric  agencies  ever  since.  Their  etfects  are  shown  iu 
the  great  mantles  of  residual  clay,  which  are  widely  distvilmtcd. 
and  in  the  phenomena  of  the  hematite  deposits.  Dr.  A. 
Schmidt,  of  the  Missouri  Stircey  of  1ST2  (Rejiort  on  Iron 
Ores,  p.  (J(i),  wrote  that  these  had  replaced  the  pre-existing 
reck,  or  had  been  deposited  in  hollows  in  the  then  existing  sur- 
face. Pumpelly,  however,  in  1885,*  advanced  a  more  probable 
h3'pothesis,  which  is  strongly  supported  bj'  F.  L.  Nason.  The 
region  is  and  has  long  been  one  of  sink-holes  caused  by  sub- 
terranean drainage  through  the  Gasconade  limestone  and  the 
caving  in,  at  times,  of  the  overlying  sandstone.  Cavities  were 
thus  afforded  in  which  ferruginous  waters  might  stand  and 
precipitate  their  dissolved   burden  of  ore.     Nason  shows  that 

•  A.  S.  Mc'Creatli,  Rep.  MM,  Secomi  Penn.  Stu-vey.  p.  231. 

"  J.  P.  Lwley,  Geol.  of  P,nn.,  1888,  Vol.  I.,  p.  311.  A.  Sherwood.  Rep. 
G,  Second  Pinii.  Sitrvei/.  pp.  33,  37,  41,  42,  GT.  A.  S.  McCreatli,  Rep.  MM, 
Second  Penn.  Survey,  p.  2r)l, 

"  A.  Sc'hinidt,  "Iron  Ores  and  Coal  Fields,"  Missouri  Oeol  Survey,  1872, 
J).  Kli). 

*  Tenth  Census,  Vol.  XV.,  p.  12. 


Flu.  2\.—Vieir  in  Cherry  Valley  Mine,  KJioirinn  Ndndstone  witli  under- 
lying cherfy  ehiy.     The  .sKndsionc  dips  Nouthcdsf  innutrd 
tointrd  t'le  orex.     After  F.  L.  Xi'son.  liepnrt  on 
Iron  Ores  of  Missonri,  2).  12:).     Plate  17. 


Fia,  22.— Seetion  oftlie  northern  end  of  the  Cherry  \'idley  Mine.     1,  Clay 
detritnn:  2.  Sandsfoni':  ;}.  Cherty  and  .slidy  el<iy:  4,  Ores';  ."i, 
Bloeks  of  sa)iiJstone.     After  F.  L.  Xason,  lie- 
port  on  Iron  Ores  of  Missonri,  p.  131. 


Fiu.  2'i.— Cross  seetion  of  the  Cherry  Valley  Mine.     1.  Sandstone;  2,  Clay 
umlehert;  8,  Sandstone  dippintj  inward;  4.  Mafpinuan 
limestone.     After  F.  L.  X((son.  Report  on  the 
Iron  Ores  of  Missouri,  p.  134. 


seve 

sauc 

fig  11] 

does 

01  la 

cap  ] 

layej 

into 

ble  tl 

Itittp] 

by  ]i 

strab 

beds 

of  de: 

Th 

Dent. 

mines 

a  mi 

about 

Th( 

at  ab( 

a  stoc 

yielde 

mnch 

were  i 

anonu 

specnl 

wbore; 

Nason 

tile  Uq', 

effect© 

>'.()•->. 

but  iiTi 


'••Ini 
'  W.  3 

Hec.  li. 
P  12.  1 
Survey,  ] 


THE  IRON  SERIES  CONTINUED. 


123 


several  of  the  largest  mines  are  along  lines  of  old  drainage 
\..lle)'s.  The  edges  or  walls  of  the  pits  are  formed  by  the 
sandstone  which  dips  inward,  as  shown  in  the  accompanying 
figures.  Just  how  nmch  overlying  rock  has  washed  away 
does  not  appear  with  all  desirable  certainty,  but  the  presence 
01  large  amounts  of  chert  mixed  with  the  ore  indicates  that  the 
cap  must  have  been  to  a  great  extent  limestone  with  interbedded 
layers  of  this  rock.  As  Nason  states'  the  limestone  that  fell 
into  the  cavities  has  been  replaced  with  ore.  It  is  very  proba- 
ble that  the  former  was  an  important  precipitating  agent  to  the 
latter.  A  fossil  crinoid  was  found  at  Cherrj'  Valley,  replaced 
by  hematite,  giving  evidence  that  even  Lower  Carboniferous 
strata  had  been  present.  The  leaching  of  these  old,  overlying 
beds  and  the  superficial  drainage  seem  to  indicate  the  method 
of  derivation  of  the  ore. 

The  most  productive  counties  are  Crawford,  Pheljis  and 
Dent,  but  smaller  deposits  occur  in  several  others.  The  largest 
mines  are  the  Cherry  Valley,  with  a  total  product  of  over  half 
a  million  tons,  the  Simmons  Mountain,  which  has  yielded 
about  half  as  much,  and  the  Meramec  with  ,'57.'), 000. 

The  total  product  of  all  the  mines  is  computed  by  Kason 
at  about  two  and  one-(piarter  millions  of  tons.  A  sample  from 
a  stockiiile  made  up  at  St.  Louis  furnaces  from  several  mines, 
yielded  Fe  50. 43,  P  0.005  (Nason,  /.  c.  p.  157),  but  many  are 
much  lower  in  iron.  In  former  years  100,000  to  '^'OO.OOO  tons 
wore  annually  produced  ;  recently,  however,  much  less.  Sumo 
anomalous  features  are  j)resented  by  these  ores  in  that  they  are 
specular  hematite  in  a  practically  unmetamovphosed  sandstone, 
wlu'veas  some  less  crystalline  form  would  naturally  lie  expected. 
Xa«on  believes  that  they  were  originally  sulphides,  and  that 
tliP  beat  generated  by  the  decomposition  of  this  mineral  has 
etYeeted  the  <*liange  to  specular.^ 

'2.02.13.  Examples.  Jefferson  County,  New  York.  Large 
Init  iiTegular  bodies  of  red  hematite  associated  with  crystalline 

'  "Iron  Ores  of  Missouri."  p.  1^8.  Mo.  Gcnl  Siir.,  1S02. 

'  W.  M.  Chaiivtniet,  Tenth  Cchhhs,  Vol.  XV.,  \S^r>,  p.  403.  F.  L.  Nason. 
"  Report  on  Iron  Ores,"  pp.  110-15(5.  21H-231.  Missotwi  Geol.  Survey,  18(^3. 
Rec.  R.  Punipelly  "On  tiie  Ori^'in  of  the  Ore,"  Tenth  Census,  Vol.  XVI., 
P  12.  Rec.  A.  Schmidt,  "Iron  Ores  and  Coal  Fields,"  Missouri  Gcul, 
Surrey,  1872,  p.  124. 


!    1 

)    ■ 


1 

--4 
1 


lU 


KEMP'S  ORE  DEPOSITS. 


limestone,  serpentine,  and  pyritous  gneiss  and  overlain  by  Pots- 
dam sandstone.      The  crystalline  limestone  is  certainly  pre- 
Cambrian,  and  would  be  called  Algonkian  in  the  later  use  of 
this  term,  and  later  Laurentian  in  the  earlier  nomenclature.' 
In  a  recently  issued  report  to  James  Hall,  State  Geologist,  C. 
H.  Smyth,  Jr.,  has    named   the    limestone    series   the   Oswe- 
gatchie.     The  ore  bodies  occur  along  a  northeast  belt,  from 
Philadelphia,  Jeirerson  County,  to  Gouverneur,  St.  Lawrence 
County,     They  range  up  to  ;J0  or  40  feet  in  thickness  and  con- 
sist of  /  "!,  earthy  hematite  in  porous  or  cellular  masses,  witli 
some  specular.     Many  interesting  minerals,  including  siderite, 
millerite,  chalcodite,  (|uartz,  etc.,  are  found  in  cavities.     The 
alignment  of  the  mines  along  a  marked  belt  has  given  some 
ground  for  thinking  them  interbedded  deposits,  and  their  asso- 
ciation with  Potsdam  sandstone  has  created  the  impression  tliat 
they  are  of  Cambrian  {or,  as  it  was  then  called.  Lower  Silu- 
rian) age.^    J.  P.  Kimball   has  stated   that  they  ai'e  replace- 
ments of  Calciferous  limestone. '     E.  Emmons  in  the  "Report  ou 
the  Second  District"  of  the  early  New  York  Survey,  regarded 
the  associated  crystalline  limestone    as    an  intruded  igneous 
mass,  and  the  same  method  of  origin  was  ap})lied  to  the  ores 
and  accompanying  so-called  serpentine.     The  latter  was  called 
reusselaerite  by  Ennnons.     Brooks  gave  the  following  section, 
tfiken  at  the  Caledonia  Mine:  1    Potsdam  sandstone,  40  feet. 
2.  Hematites,  40  feet.     3.  Soft,  schistose,  slaty,  green,  magne- 
sian  rock  with  pyrite  and  graphite,  OO  feet  plus.     4.  Gramdar, 
crystalline  limestone,  with  phlogopite  and  graphite.     5.  Sand- 
stone (like  1).  If)  feet.     0.  Crystalline  limestone  with  beds  and 
veins  of  granite.     C.  H.  Smyth,  Jr.,  has  recorded  the  strati- 
graphical  observations,  cited  earlier,  and  lias  formulated  tlie 
following  explanation  of  origin.     The  lineal  arrangement  of 
the  ore-bodies  is  referred  to  their  association  with  a  great  stra- 
tum of  pyritous  gneiss  belonging  to  the  Oswegatohie  Series. 
This  weathers  deeply  and  becomes  light  and  porous  (constitut- 


'  C.  H.  Smyth,  Jr.,  "Geological  Reconnaissjince  in  the  Vicinity  of 
Gouverneur,  N.  Y.."  Trans.  K  Y.  Acad.  Scl,  XII.,  97,  1S!)3.  "Report  on 
Jefferson  and  St.  Lawrence  Counties, "  i^'j).  of  N.  Y.  State  Oeol.,  1893, 
4fl;i     Also  l«i».-),  481. 

»  See  T.  B.  Brooks,  Amer.  Jonr.  Scl,  iii.,  IV.,  23. 

=  J.  P.  Kimball,  Amer.  acologist,  December.  18i)l,  p.  308. 


THK  IRON  SERIES  CONTINUED. 


135 


ing  thus  a  "fahlbaiul").  It  contains  conHiderable  dissemi- 
nated magnetite.  The  so-called  serpentine  or  rensselaevite  only 
occurs  in  association  with  ore,  and  itself  varies  in  character, 
so  that  one  is  justified  in  regarding  it  as  an  altered  form  of 
several  different  kinds  of  rocks.  Smyth  infers  that  tlie  decay 
of  the  ferruginous  minerals,  but  especially  of  pyrite  in  the 
pyritous  gneiss,  has  furnished  the  iron-bearing  solutions,  which 
following  down  the  dip  have  re})laced  the  crystalline  limestone 
where  the  presence  of  intruded  granites  or  the  flattening  of  the 
(lip  checked  the  circulations.  The  action  of  the  acidulated  fer- 
nii^inous  waters  has  altered  the  granites  and  gneisses  in  the 
limestone  series  to  the  so-called  serpentine.^  These  views  are 
fortified  by  microscopic  sti  dy  of  the  rocks,  and  though 
advanced  only  as  an  h3'pothesis  are  worth}'  of  great  confidence. 

The  mines  have  afforded  in  the  past  a  moderately  rich  (.')() 
to  '^^^%  Fe),  non-Bessemer  ore.  The  best  known  and  largest 
producers  are  the  Old  Sterling,  the  Caledonia  and  Kearney 
properties,  but  they  are  not  now  operated  and  are  not  likely  to 
be  reopened  in  the  immediate  future. 

•^.()-M4.  Example  9.  Lake  Superior  Hematites.  Bodies 
of  hematite,  both  red  and  specular,  soft  and  hard,  anhydrous 
and  somewhat  hydrated,  associated  with  jaspers  and  cherts, 
and  deposited  by  the  replacement  of  cherty  iron  carbonate  with 
iron  oxide,  in  troughs,  formed  by  some  relatively  impervious 
rock.  The  impervious  rock  is  usually  a  decidedl}'  altered  igne- 
ous dike,  now  hornblendic  and  dioritic,  but  one  that  has  been 
originally  diabase.  Tlie  trough  may  be  formed  b}'  a  folded  dike ; 
by  two  or  more  intersecting  dikes;  by  the  intersection  of  a  dike 
and  a  compact,  sedimentary  stratum ;  or  less  commonly  by  a 
folded  bed  of  slate.  All  of  these  varieties  are  known  in  one 
place  and  another.  Increasing  study  has  shown  that  the  paral- 
lelism in  the  structure  of  the  several  districts,  in  the  associates 
of  the  ore,  and   in  the  geological  horizons  at  which  the  ore 

'  T.  B.  Brooks,  "On  Certain  Lower  Silurian  Roeks  in  St.  Lawrence  Co., 
New  York,"^mer.  Jour.  Scl,  iii.,  IV.,  p.  22.  Rec.  G.  S.  Colby,  Jour 
U.  S.  Ansoc.  Charcoal  Iron  Workern,  XL,  p.  2(i3.  E.  Emmons,  N.  Y.  Geol. 
^in-reji.  Second  Dixtrict.  p.  O.*?.  T.  S.  Hunt,  "  Mineralof^y  of  the  Lauren- 
tiiin  Limestones  of  North  America."  ::'liit  Ann.  Rep.  Regents  K  Y.  State 
('»ii'.,  1871,  p.  88.  J.  C.  Smock,  Bull  N.  Y.  State  Mus.,  No.  7.  1889.  p  44. 
l^ec.  C.  H.  Smytli,  Jr.,  in  Report  of  N.  Y.  State  Geologist  for  1894,  and 
Joiirnul  of  Geology,  II.,  G78,  1894.     Rec. 


tliat  f(j 
silifoi 


tl) 
If 


('■'^e  si 
iiroiil 


new  jnl 
onti 


SKI 


tioualli 
t] 


i<»  Sou 


tl 


lt> 


K<'' 


H.  L. 

foJJo 
based. 


wii 


Tiiii  IRON  si-:rihh  contlwkd. 


lar 


occurs,  is  pronoimced.  Magnetite  is  ut  tinien  j)resent  and  linio- 
iiitos  have  been  miued  to  a  limited  degree.  There  are  five 
luincipal  oro-produeiug  belts  or  districtH,  which  are  also  called 
in  instances  "ranges,"  as  the}'  follow  ranges  of  low  hills.  They 
are,  in  the  order  of  tlieir  chronological  exploitation,  tlie  Mar- 
(jiiette,  just  south  of  Lako  Sujjerior,  in  j\lichigan;  the  JMenonii- 
nee,  on  the  aontiieru  border  of  the  Upper  P^eninsula  and  partly 
in  Wisconsin;  the  Gogebic  or  Penokee-Gogebic,  on  the  north- 
western border  between  Michigan  and  Wisconsin;  the  Vermil- 
ion Lake,  in  Minnesota,  northwest  of  Lako  Superior;  and  the 
Mesabi  (Mesaba),  in  the  same  general  region  as  the  last. 

^.O'^.  IT).  The  geology  of  theso  districts  has  been  a  snbject  of 
much  controversy,  not  alone  in  the  relations  of  the  separate 
aroas,  but  in  the  subdivisions  of  a  single  one.  The  ever-pres- 
ent ditliculty  of  classifying  and  correlating  metaniorphic  rocks 
lias  here  been  very  great.  ^Moreover,  there  are  other  sejiavate 
districts,  of  related  geological  structure,  which  ought  also  to 
lie  hrought  into  harmony,  and  only  at  a  very  recent  date  has 
thin  heen  even  partially  attained. 

2.(i'2.1t'>.  The  ores  and  their  inclosing  rocks  have  usually 
heen  called  Huronian,  as  this  is  the  name  formerl_y  applied  to 
the  schistose  and  metaniorphic  rocks  overlying  what  was  con- 
ceived to  be  the  basal,  gneissic  Laurentian.  The  geoh'gists  of 
the  United  States  Geological  Survej'  have  essentially  modified 
this  nomenclature,  and  have  restricted  Archean  to  the  earliest 
crystalline  or  metamorphosed,  igneous  rocks  that  precede  the 
.first  sediments.  Algonkian  is  then  emploj'ed  for  the  first  and 
snhsequeut  sedimentary  rocks,  and  for  the  igneous  intrusions 
that  followed  the  first  sediments  up  to  tbo  ojieningof  the  fos- 
siliferous  Cambrian.  The  ditliculty  of  correctly  correlating 
those  strata  with  the  original  Huronian  prompted  the  step,  but 
Huronian  is  still  in  very  general  use  and  Algonkian  and  the 
new  meaning  of  Archean  have  received  but  moderate  support 
outside  of  the  Survey.  In  later  years,  however,  the  excep- 
tioually  difficult  geological  problems  in  the  iron  ore  districts  on 
the  south  side  of  Lake  Superior  have  been  especially  solved  by 
tiie  f^'cologists  of  the  U.  S.  Survey,  Irving,  Van  Hise,  Bayley, 
H.  L.  Smyth,  and  others,  and  it  is  upon  their  work  that  the 
following  descriptions  for  the  three  districts  in  question  are 
based.     The  references  in  the  footnote  following  will  place  any 


ViH 


h'/orrs  o /,'/•;  ih:i'osits. 


reader  in  touch  with  the  earlier  literature,  reviews  of  whirli 
will  he  found  in  the  eitatiouH  from  Yau  Hise,  A.  Winehell  and 
WadHWorth.'  The  north  hhoredistrietH  arealwo  closely  rehitcd, 
and  as  a  {geological  prohleui  account  must  he  taki'n  an  well  of 
tluM)riginal  Jliu'onian  area,  north  of  Lake  Huron,  aud  of  the 
Kaministi(iuia  aud  Jtaiuy  Lake  regions  north  of  Lake  Supe- 
rior, although  they  contain  no  iron  ores." 

2.05J.1?.  Tlie  oldest  or  pre-sedimeutarj-  rocks  (Archean) 
consist  of  massive  granites,  gneissoiil  granites,  syenites,  perido- 
tites,  greenstone  schists,  and  other  sciiists  tiiat  are  sheared  and 
metamorphosed  igneous  nn-ks  and  tutfs  of  various  kinds.  They 
were  called  the  "Fundamental  Complex"  hy  Irving,  and  the 
nanie  in  the  form  of  "Basement  Complex"  has  heen  retained 
in  the  later  work.  Further  investigation  may  clear  up  its 
stratigraphical  relations  to  a  certain  extent.  The  Archean  is 
succeeded  l)y  the  formations  of  the  Algonkian,  which  involve 
or  succeed  imdouhtod  sediments.  In  the  south  shore  iron 
ranges  the  Algonkian  has  been  quite  uniforndy  found  to  be 
divisible  into  two  series,  which  are  separated  by  an  unconform- 
ity and  a  considerable  period  of  erosion.  The  lower  is  called 
Lower  Huronian.  Lower  Marquette,  Keewatin,  Lower  Vermil- 
ion, and  Menominee  proper  in  the  different  exposures,  and  jirob- 
ably  the  great  clierty  limestone  of  the  Penokee-Gogebic  series 
is  its  local  ecpiivaleut.  In  the  Marquette  district  "Wadsworth 
has  recently  divided  it  still  further  into  the  Republic  and  Mes- 
nard  formations.  The  upper  part  follows  an  unconformity  and 
is  called  in  the  different  regions  L^pper  Huronian,  Animikie, 
Upper  Vermilion,  Upper  IMarquette,  Western  Menominee,  aud 

cJ.  R.  Van  Hise,  "An  Attempt  to  IJarnionize  Some  Apparently  Con- 
flicting Views  on  Lake  Superior  Stratigraphy,  Amer.  Jour.  Sci.,  ii. ,  XLI., 
117;  Tenth  Annual  Report  Director  U.  S.  Geol.  Survey.  Van  Hise, 
Bayley  ami  Smytli,  MoHogra]>h  XXVIII.  of  U.  S.  Gcoloyical  Survey  on 
the  Geology  of  the  Marquette  Iron  District.  A.  Winehell,  "  A  Last  Word 
with  the  Huronian,"  Bull.  Geol.  Soc.  Amer.,  II.,  85.  M.  E.  Wadswortli 
"  Notes  on  the  Geology  of  the  Iron  and  Copper  Districts,"  1880. 

'  The  following  jmixMs  (U'ul  with  the  ores  in  general:  D.  N  T.acoi 
Development  of  Lake  Sui)t'rior  Iron  Ores."  Trans.  A)iier.  1         '' 
XXVIL,  341;  .John   Birkiiihine,   "The  Resources  of  the   ,  Siii 

Region,"  Idem,  XVI.,  KiH,  1H8T;  "The  Iron  Ore  Supply,"  7.    .//.  XX^ 
519:  H.  V.  Winehell,  "  Historical  Sketch  of  the  Discovery  of  Minera'  I'e- 
posits  in  the  I.ake  Su^xsrior  Basin,"  Proc.  Lake  Superiar  Min.  Iiisi      i. 
contains  a  bibliography.    See  also -Imer.  Geologist,  XIII.,  104. 


THE  rno.y  sfjuich  contixikd. 


129 


Ponok(M>Gogi>l>ic  |)r<)|)pr.  For  tlie  Mjir(|uottt*  region  tliiH  lias 
alxo  been  further  tlividcd  by  WadHWortli  into  two,  tlio  llolyoke 
iiiid  tlm  Negftuneo  formations.  It  is  nuicli  loss  niotaniorpliosod 
than  tho  lower  niomher,  and  in  tho  I\Ian|uett(»  district  contains 
sonio  (m>.  In  tho  Menoniinoo  rc}j;ion  of  Wisconsin  it  affords 
the  deposits  th(>re  wrought  and  carries  the  on^  in  the  (fogehic 
niiige,  Jiigher  in  tho  section,  alter  another  unconformity  fol- 
jdws  tho  Kevveenawan  (K(>weenian)  or  Nipigon.  'J'his  closes 
tlic  Algonkian.  Still  above  is  the  Cambrian  (Eastern,  West- 
»'rn  or  Potsdam)  sandstone. 
•.'.(»•!.  IS.     Example  l»a.     Marquette  District.    Tho  Manjuette 


]}■ 


Fio.  25.— Generalized  section  iirross  the  Marquette  Tron  RaiKje,  to  illustrate  the 
type  of  foUh.     After  ('.  It.  Von  HLv.  Fifteenth  Ann.  Hep. 
Dir.  L\  <S.  (leuloyieai  tiurvei/,  p.  48.1. 


district  was  earliest  known  and  has  been  most  thoroughly  stud- 
ied ;  but  owing  to  the  confused  geological  structure,  there  has 
heen,  as  already  remarked,  much  discordance  of  interpretation. 
The  remarkably  careful  and  systematic  work  of  Van  Hiso  and 
I'.ayley'  has.  however,  cleared  up  the  greatest  diflficulties.  In 
the  .Mar(iuette  district  the  Algonkian  (or  Huronian)  rocks  form 
■d  synclinorium  or  synclinal  trough,  resting  in  the  older  Archean 
crystallines  and  extending  from  Marciuette  on  Lake  Su])erior, 
westward  in  a  nearly  east  and  west  line.  While  the  axis  of  the 
iiiiiin  syncline  runs  east  and  west,  there  are  many  minor  folds 
paiiillel  with  this,  which  are  overturned  outwardly  from  the 

'  ('.  R.  Van  Hise  and  W.  S.  Bayley,  "  Preliminaiy  EeporTon  the 
Maiiinette  Iron-bearing  District  of  5Iii-liigan."  with  a  C'hai)ter  on  the 
'•'•I'ui.lic  TroiiKli,  l)y  H.  L.  Smyth,  Fifteenth  Amiual  Keport  Director  U.  S. 
(Irol.  Surrei/,  4s,-)-(i.-)0.  Tliis  report  slioiild  be  in  the  hands  of  every  one 
interested  in  tiie  region.  See  also  Monogmph  XXVIII,,  which  with  its 
atlas     the  fullest  exiwsition  of  the  sui>ject. 


a 


133 


KEMP'S  ORE  iJEPOSITti. 


center  as  in  the  accompanying  figure,  after  Van  Hise.  Some 
markotl  folding  lias  also  occurred  at  right  angles  to  the  east 
and  west  axis.  Faulting  is  almost  entirely  lacking,  and  the 
topographic  relief  is  (piite  entirely  due  to  the  relative  resist- 
ances presented  by  the  several  rocks  to  erosion.  All  are  more 
or  less  metamorphosed  and  have  evidently  suffered  severely 
from  pressiu'e  and  shearing  stresses.  The  Lower  Marciuette  is 
chietly  developed  at  the  eastern  end  and  around  the  rims  of  the 
synclinorium.  as  it  was  from  this  end  that  the  shore-line  seems 
to  have  advanced  upon  the  ancient  land.  It  begins  with  the 
Mesnard  quartzite,  110  to  070  feet  thick.  Above  come  in  order 
the  Kona  dolomite,  425  to  1,375  feet;  the  Wewe  slate,  550  to 
1,050  feet;  the  Ajihik  quartzite,  TOO  to  900  feet;  the  Siamo 
slate,  '^00  to  (j'^5  feet;  and  the  Negaunee  iron  formation,  1,000 
to  1.500  feet.  In  Figs.  'l^\  and  "^7  all  these  except  the  Negaunee 
are  grouped  under  on<^  sign.  The  total  thickness  varies  from 
'•i,'.t75  to  6,1''20.  The  Upper  Marquette  includes  from  below 
upward,  the  Ishpeining  formation,  including  the  Goodrich 
(juartzite  and  the  Bijiki  schist;  the  Michigamme  formation 
of  slates  and  mica  schist;  and  the  Clarksburg  formation  of 
more  or  less  altered  volcanic  rocks.  Upon  Figs.  'li\  and  27 
the  Ishpeming  has  one  sign  and  the  Michigamme  and 
Clarksburg  another.  In  the  mining  district  the  total  thick- 
ness of  the  Upper  ]\Iar(piette  is  less  than  5,000  feet.  Except 
as  regards  the  Goodrich  (juartzite  of  the  Ishpeming  and  some 
small  limonite  deposits  in  the  Michiganmie  formation  the 
divisions  have  no  economic  importance.  In  the  Lower 
]\[ar(jni;tte  the  economic  interest  centers  in  the  Negaunee 
formation,  which  is  much  the  most  important  of  all.  Later 
than  all  these  just  cited  are  intrusions  of  basic  dikes  that  have 
betn  prime  factors  in  the  ore  deposition. 

The  Negaunee  formation  in  its  completest  section  consists 
from  below  upward  of  sideritic  slate  and  gruuerite-maguetite' 
slate;  ferruginous  slate;  ferruginous  chert ;  and  at  the  top  of 
jasperite  or  jasper- rock;  but  not  all  of  thee  are  necessarily 
present  in  any  one  section.  The  ores  are  either  "soft  ores"  or 
"hard  ores."  The  former  are  blue,  red  or  brown,  earthy  aud 
somewhat  hydrated  varieties  of  hematite,  and  resemble  onli 


•  Griinerite  is  a   variety   of   ainpliiboU;  or  hornblende.     It  is  an   inm 
amphibole. 


Mi 


>e 
st 
le 
it- 
re 

'ly 

is 
he 
ms 

the 
;ler 
» to 

1110 

000 

uee 

L'oni 

low 

rich 

tioii 

1  of 

il27 
and 
iok- 

Icept 

loino 
the 
Aver 

Ult'O 
lUtt-T 

liavfi 


■^ists 
Jitite' 

\V  ^'^" 
irily 

or 

aii>l 

bnli 


iron 


Fia.  29. — Open  cut  in  the  Rcjmhlu'  mine,   Maiypwtfe  rmnje,   siiouinij  a 
horse  ofjaK2)er.     From  <t  photograph  by  H.  A,  Wheeler. 


liii 


THE  IRON  HEItlES  CONTINUED. 


133 


nary  dirt  of  these  colors,  with  small  lumps  '^f  ore  scattered 
throughout.  They  strongly  simulate,  limoiiite  hut  are  not 
so  hydruted.  The  soft  ores  are  now  the  main  object  of 
mining,  but  they  were  earlier  looked  upon  with  disfavcn- 
and  only  the  hard  ores  were  sought.     The  haid  ores  are  mas- 


Fl«.  38. — Cross.srrfioii/)   to  I'lh/i^frtitr  tin  orcurrenrp  nnd  nxforhitionn  of 
iron  ore.  in  tin  Marqnitti'  district,  Mii-fiif/an.     After  ('.  li.  Vim  Uixc, 
Amer.  Jour.  Scl.,  Fthrnnri/,  18{)"3:  Eiif/iiu'cring  ai>d  Mining 
Jnurnii'.Jii/i/Q.  1S!)2. 

sive  or  micao«^ons  specular  hematite,  rarely  magnetite,  and  are 
blastod  out  in  lumi)S.  Van  Hise  makes  three  classes  of  depos- 
its: (1)  Those  at  the  bottom  of  the  iron-hearing  formation;  (2) 
tlinse  within  it;  and  (o)  those  at  its  top.  including  also  some 
that  run  up  into  the  Goodrich  (piartzito.  the  lowest  stratum  of 


134 


KEMP'S  Olil'J  DKrOSlTS. 


m 


the  overlying  Islipeiniug  formatiou.  The  hard  ores  belong 
to  the  third  class.  All  tiiese  classes  rest  upon  an  impervious 
rock  of  some  sort,  and  lie  in  a  pitching  trough  formed  by  it. 
The  trough  may  be  a  fold  in  the  Siamo  slate,  and  often  is  for 
ores  of  the  first  class.  It  may  be  a  single  folded  dike,  Avhich 
is  an  altered  diabase,  now  called  soapstone  or  paint-rock  by  the 
miners.  These  are  shown  in  the  cuts  of  Fig.  2.S.  The  trough 
may  result  from  the  intersection  of  two  or  more  dikes,  as  is 
more  fully  illustrated  under  the  Vermilion  district.  In  all 
cases  it  seems  evident  that  after  the  close  of  the  time-period  rep- 
resented by  the  Upper  JMariiuette,  and  after  the  intrusion  of  tlio 
basic  dikes,  the  overlying  ferruginous  rocks  were  subjected  to 
extensive  leaching  of  their  iron,  by  descending  atmospheric 
waters,  charged  with  carbonic  acid.  When  these  came  to  rest 
in  the  troughs,  or  met  other  descending  currents,  which  were 
cliarged  with  oxj^gen,  and  which  had  percolated  downward 
along  the  dikes,  the  dissolved  proto-salt  of  iron  was  oxidized 
and  precipitated  as  ferric  oxide,  replacing  the  cherts  or  other 
siliceous  rock  that  bad  previously  tilled  the  trough.  The  sil- 
ica is  thought  to  have  been  in  large  part  removed  by  alkaline 
sohitions  emanating  from  the  diabase.  These  changes  were 
facilitated  by  the  fact  that  the  brittle  cherts  bad  been  nnich 
shattered  during  the  folding,  and  this  condition  contributed  to 
the  formation  of  the  scft  ores  in  their  fragmental  condition. 
The  hard  ores  ajipear  to  owe  their  condition  to  the  dynamic 
metamorphism  that  has  been  particularly  strong  along  the  con- 
tact line  of  the  Upper  and  Lower  Marcjuette.  The  micaceous 
ores  certaiidy  owe  their  structure  to  shearing.  The  magne- 
tites are  supposed  to  be  former  hematites,  that  have  suffered 
partial  reduction  hy  infiltrating  solutions  charged  with  organic 
matter.  They  are  best  developed  in  the  Republic  tongue  of  the 
main  trough. 

2.0-2.21.  The  origin  of  these  ore  bodies  has  been  a  subject 
of  much  controversy.  A  review  of  the  various  hypotheses  up 
to  1880  is  given  in  Wadsworth's  monograph'  and  a  still  later 
one  is  given  in  the  monograph  of  Van  Hise,Bayley  and  Smytb." 

»  M.  E.  WadsM'orth,  "  Notes  on  the  Irou  and  Copi^er  Districts  of  l^ke 
SuiKnior,"  Bull.  Mm.  Comp.  Zool ,  Vol.  VII.,  No.  1.  July,  ISHO. 

"  Van  llise,  Biiyley  and  Sinylli,  "Tlio  Mai<iu('tte  Iioii-bearing  District 
of  Michigan,"  Monograph  XXVIII.  U.  S.  Geological  Survey,  pp.  J^148, 
1«97. 


■J. 
1.S87, 
of  lIV.v, 
der  (ihe 
<7c.s.,  ! 
and  \V 
18,-il. 
Oro.s  of 
"I'reliii 
we.steru 


^gasg^g^ 


THE  IRON  SKRIEH  CONTfNUED. 


135 


The  early  survey  of  Foster  and  Whitney  (IS')])  attributed  an 
eruptive  origin  to  them  and  the  same  difficult  thesis  has  been 
supported  by  Wadsworth  (18H0).  Otliers  formerly  regarded 
tliem  as  old  limonite  beds  in  a  sedimentary  series  that  was 
subse(iuently  mettimorphosed.  Ciedner  (18(il)),  Brooks  (1873), 
and  others  saw  reason  for  it;  but  there  is  little  doubt  that 
the  origin  outlined  above  is  correct.  While  the  present  text 
follows  the  recent  work  of  the  U.  S.  Geological  Survey,  be- 
cause it  is  more  detailed,  comprehensive  and  really  accurate 
than  any  other  available,  and  because  space  is  necessarily 
limited,  yet  the  reader  who  would  thoroughly  acquaint  him- 
self with  the  questions  under  discussi(jn  Hhould  consult  the 
citations  given  below,  especially  those  from  Brooks,  Irving, 
Wadsworth  and  Rominger. 

2.02.22.  It  was  in  the  forties  that  the  importance  and  extent 
of  the  ore  bodies  were  first  vaguely  suspected.  The  trt)uble 
that  they  made  with  the  compasses  of  the  early  land  surveyors 
indicated  their  existence.  Important  mining  began  in  1S54. 
Soinewliat  over  100,000  tons  were  produced  in  iSdO,  over  800,- 
000  in  1S70,  nearly  l,r)00,000  in  ISSO.  In  1877  the  Menominee 
region  was  opened,  and  in  1885  the  Penokee-Gogebic  and  Yer- 
nii'ion  districts  began  to  ship.  The  total  shipments  from  the 
Lake  Superior  region  in  1890  were  8,1)82,5:31  tons.  The  total 
production  through  1807  of  the  Marquette  district  was  40,253,- 
222  tons.  A  ijuite  complete  citation  of  the  literature  is  to  be 
found  in  Wadsworth's  monograph,  already  referred  to;  in  Irv- 
iug's  "Copper-bearing  Rocks  of  Lake  Superior,"  Jifonograph 
v.,  U.  S.  Ge:)l.  Survey;  and  in  Van  Hise,  Bay  ley  and 
Smyth,  Monograph  XXV III.  See  also  imder  Examples  0/>,  Of", 
and  Od.  Onlj'  the  most  important  or  most  recent  papers  are 
mentioned  here.' 


'  J.  Birkiubine,  "Resources  of  the  Lake  Superior  Distriot,"  M.  E.,  July, 
1S8T.  T.  B.  Brooks,  a<ol.  Siirvc;/  of  Mirhigan,  Vol.  1..  llS7:i;  Geol.  Snrvr?j 
of  WiNConsin,  Vol  III.,  p.  -loO.  11.  Creiiner,  "Die  vorsilurischen  Gebilde 
deroberen  Halbinsel  von  Michigan  in  Nord  Anierika,  "  Zcituch.  d.  d.  Geol. 
r?f.s.,  18i;9,  XXL.  nil!;  also  Berff-und  ITuU.  Zeit.,  1871.  p.  8fi9  Foster 
ami  Whitney,  Gvol.  of  the  Lake  SiijHTior  District,  Vol.  I.,  "Ir,,n  Lands," 
ISol,  R.  D.  Irving.  "On  the  Origin  of  the  Ferniginous  Schists  and  Iron 
Ores  of  the  Lake  Siif)erior  Region."  Aiiirr.  Join:  Sci..  iii.,  XXXII.,  203; 
"  I'reliminary  Pai)er  on  an  Investigation  of  the  Archean  of  the  North- 
western States,"  Fifth  Ann.  Hep.  Director   U.  S.  Geol.  Survey,  p.   131; 


1    ; 


130 


KEMP'S  ORE  DEPOSITS. 


2.02.23.  Example  0/>.  Menominee  District.  Tlie  Menomi- 
nee River,  which  j^ives  the  district  its  name,  forma  the  south- 
easterly boundary  between  tiie  Upj)or  Peninsula  of  Michigan 
and  Wisconsin,  The  mines  are  situated  about  forty  niilo.s 
south  of  the  Marcpiotte  grouj),  and  the  same  distance^  west  of 
Lake  Michigan.  'J'iie  larger  number  are  in  ^Michigan,  but  the 
I)rt)ductive  b(;lt  extends  also  into  Wisconsin,  They  lie  along  the 
south  side  of  an  east  and  west  range  of  hills,  which  rises  from 
200  to  300  feet  above  the  surrounding  swampy  land.  Begin- 
ning with  the  base  and  inchided  in  tlie  lower  Menominee  accord- 
ing to  H.  L.  Smyth,  tlie  geological  section  is  as  follows,  all  of 

Sex'enth   Ann.  Rep.,  p.   4:U ;  also   Adniinistnitive    Keports  in   subsequent 
volunu's.     J.  E.  .Joplinpj,  "Tlie  Marquette  R;inge:     Its  Discovery,  Devel- 
opment,   and    Kcsouri-es,"    Traii.'i.   Anivr.   Inst.   Min.    Eng.,   XXVII.,  ')4\. 
J.  V.  Kinil)all,  "The  Iron  Ore  of  the  JIaniuette  District,"  ^Imcr.  Janr.  uf 
ScL,  ii..    XXXIX.,  290.     H.  S.  Minn-ne.   Srlionl  of  ^fin(\',  QnarfoHi/.   II.,  ]>. 
413.     E.  Keyer,  "  (leologieder  Anierikanisclien  I'jsenei/la<;erstatten  (inshe- 
sonden  Michigan)."  Oest.  ZeitHch.  f.  Berg-  a.  Hittt..  Vol  XXXV.,  pp.  liO, 
l:n.  1887.     C.  Roniinj^er.  O^'ol.  Siirrci/  of  Mieliiijun.  Vol.   IV.,  18H4.     "Re- 
])ort  ou  the  Iron   auil  Copper   Regions.  1881-84.  Idem.  Vol.  V..  1895.    C.  R, 
Van  Hise,  "An  Attempt  to  Harmonize  Some  Apparently  Condicting  View.s 
of  Lake  Sujierior  Stratigraphy,"  Ainer.  Jour.  Sei,  iii.,  XLL,  p.  117,  Feb- 
ruary,   18(M:  Tenth   Ann.  Rep.   Direetor   U.  S.    Gcol.   Survey;  '  The  Iron 
Ore.s  of  the  Marquette  District  of  Michigan,"  .!;«('/•.  Jonr.  Sei.,  Februaiy, 
1893,   p.   IIT).     J5tli  AnniKil  Report  Direetor  (J.  S.  Geol.  Survey,  pp.  485- 
057.     Van  Hise,  l^ayley  and  Smyth.    •  The  Marquette  Iron-bearing  District 
of   Michigan,"  Mono.   XXVIII    and   Atlas    U.   S.    Geol.    Surrey.     M.    E. 
Wadsworth,  "Notes  ou  the  Iron  and  Copper  Districts  of  Lake  Superior," 
Bull.  Mn.s.  Comp.  Zool.  VII.,  1,  18S0;   ••On  the  Origin  of  (he  Iron  Ores  of 
the  Marquette  District,  Lake  Superior,"  J^roe.  Bo.'if.  Soe.  Aat.  Hist..  Vol. 
XX.,  p.  470;  Engineering  and  Mining  Journal,  Oct.  29,  1881,  p.  28(i;  ...4»)*. 
Rep.  Mieh.  State  Geologist.  1891-92.      "The  Ceology  of  the  Lake  SiqH'rior 
Region,"  in  a  pamphlet   issued  by  the  Dululli,  South   Shore  &  Atlantic 
R.  R.,  1892.     Dr.  Wadsworth  announces  a  new  subdivision  of  FonnatioiiH 
in  this  and  in  Anier.    Jour.   Sci.,    January.    Is9:!.    p.   7;>.     II.  Wedding, 
Zeitseh.  f.  Berg-,  Ililtt-.  nnd  Salinenwesen  in  Preus.  Staat.,  XXIV.,  j). ;!:!!). 
C.  E.  Wright  and  C.  D.  Liiwton.   Rejis.  of  the  Conimissiouers  of  Mine  ml 
Statisties  of  Mieliigan,    1880,   and  annually  to  date.     G.   II.  William;-. 
"Greenstone  Schist  Areas  of  the  Menominee  and  Manpiette  Regions  of 
Michigan,"  introduction    by  R.  D.  Irving.  Bull.   (iJ,    U.   S.    Geol.   Surviij. 
H.  V.  Winchell,  "  Historical  Sketch  of  the  Discovery  of  Mineral  Deposits 
in  the  Lake  Superior  Region,  Proe.  Lake  Superior  Miui\ig  lust  ,  II.  II 

A  careful  compilation  of  analyses  of  oi'es  from  all  the  larger  mines  of 
the  four  older  range-s  is  given  by  Geo.W.  Goetz,  Tra)is.  Ant.er.  Inst.  Mi'i- 
Eng.,  XIX.,  .59.  1890. 


THE  IRON  SERIES  CONTINUED. 


137 


which  rests  on  the  Archean  cryHtallines:  ].  A  l):iHal<inartzite, 
rarely  conglomeratic,  1,000  feet  thick  as  a  niaxiuuini,  ami  at 
least  700  feet  over  wide  areas.  'I.  A  cryHtalline  limestone.  700 
to  1,000  feet  thick,  anil  possibly  reaching  1,500  to  ^.000  on  the 
Fence  River.  This  was  eailier  called  by  Roniinger  the  Norway 
limestone.  •'{.  Red,  black  and  green  slates  that  are  not  known  to 
exceed  200  to  oOO  feet.  Tlie  slates  here  and  tlun-e  contain  the  iron 
formation  that  affords  the  rich  ores  of  Iron  Monntain  and  Nor- 
way. In  the  southern  portion  the  horizon  of  the  slates  is  in 
part  occupied  by  altered  eruptives,  which  may  thicken  up  to 
■.',(•00  feet  on  the  Fence  River.  4.  The  Michigamme  jasper,  a 
greatly  altered  ferruginous  rook,  usually  carrying  appaiently 


Fi(i.  .30, — Plan   of  the   Ludington   ore  horl//,   Mennminre    district,  Michigan. 
Aftir  P.  Larsson,  'J'nnis.  Ainer.  In.st.  Miii.  Ehg.,  XVI.,  11!). 

fnigmental  quartz  grains.  The  rock  is  best  developed  at  Michi- 
gamme Mountain,  S.  4,  T.  43  N.,  R.  31  W.  It  is  variable  but 
appears  to  have  originalh'  been,  in  part  at  least,  a  clastic  sodi- 
niciit.  Infiltrating  iron  salts  and  the  formation  of  cherty  sil- 
ica have  In-onglit  about  the  alteration  of  the  rock. 

Iron  ores  are  met  at  three  horizons  in  this  section.  The  low- 
est is  in  the  (piartzite.  No.  1,  not  far  from  its  junction  with  the 
liiiii'stfme.  It  has  yielded  but  one  workable  deposit  The 
great  majority  of  the  ore  bodies  is  in  the  slates,  No.  3.  They 
occur  as  local  concentrations  in  a  ferruginous  rock  composed 
of  banded  jasper  and  iron  ore.  The  ferruginous  rock  is  met  at 
various  horizons  in  the  slates.  The  third  ore-bearing  forma- 
tion is  the  Michigamme  jasper,  but  the  ore  bodies  are  small.' 

'  Tho  above  is  onndensed  from  H.  L.  Smj'th,  "  Relatious  of  the  Lower 
Mpnoniiiioe  and  Lower  Marquette  Series  in  Michigan  (Preliminary)," 
Amcr.  Jour  Sci.,  Marcii,  i8',)4,  21<i.    Further  correlative  notes  are  given  in 


Ill 


138 


KBJMP's  OHM  jJEPOsrm 


The  Michif^anniie  jasper  is  correlated  by  Smyth  with  the 
Negamiee  formation  of  the  ]\rar<|uetto  district,  and  this  briiigH 
the  ])'i'incipal  ore  l)earin}jj  stratum  of  tlie  ^renominee  range 
below  the  ore- bearing  formations  in  the  jMarcjuette. 

In  the  black  slates  of  the  Upper  or  Western  Menominee 
there  are  still  other  ore  bodies,  such  as  those  of  the  Common- 
wealth and  Florence  mines,  and  at  the  Quinneseo  mines.  A 
goodly  mass  of  soft  bine  ore  was  obtained  in  the  Potsdam  sand- 
stone, which  had  evidently  been  eroded  from  the  older  ores 
diM'ing  the  deposition  of  the  Potsdam.  Greiit  geologic  interest 
has  been  felt  in  the  metamor{)hism  of  the  eruptive  rocks  in  tlio 
Menominee  district,  and  altliough  remotely  related  to  the 
geology  of  the  ores,  attention  should  be  directed  to  the  valua- 
ble paper  of  G.  H.  Williams  cited  below. 

Since  IHIK)  W.  S.  Gresley  of  Erie.  Pa.,  has  been  collecting 
from  the  ore  piles  in  that  city  most  extraordinary  slabs  of  ore, 
chiefly  from  the  Chapin  mine,  of  the  Menominee  range,  that 
contain  irrpressions  bearing  the  closest  resemblance  to  alg?e, 
or  other  low  forms  of  plant  life.  They  may  be  the  long-sought 
fossils  of  Huroniau  times.* 

The  Menominee  ores  are  generally  soft,  blue-earthy  hema- 
tites, which  give  a  red  ]iowder  and  consist  of  finely  divided 
particles  of  specular.  Brown  hematit  are  very  limited.  A 
lenticular  shape  is  more  pronounced  tlian  in  the  Marquette 
district  and  the  concentration  of  the  ore  has  not  been  shown  to 
be  connected  with  intruded  (likes  as  elsewhere,  although  the 
cheiuical  reactions  involved  are  doubtless  the  same.  The  gen- 
eral strike  is  about  N.  7b°  W.,  and  the  dip  70°  to  80°  N.  They 
also  pitch  diagonally  down  on  the  dip.  (Cf.  New  Jersey  j\lag- 
netifes.  Example  I'-id.)  There  has  been  produced  including  JS'.)7 
a  grand  total  of  24,031,441  tons  since  mining  began. '^ 


C  R.  Van  Hise's  pjijier  on  tlie  Marquette  range,  in  15th  Ann.  Rep.  Dir.  U.  S. 
Geol.  Sui'vcif,  p.  (i47.  Smyth  lias  also  given  an  excellent  short  sketch  at 
the  close  of  his  pai)er  on  "]\higiietic  Ohservations  in  Geological  Mapping," 
Trans.  Amer.  Inst.  .Vin.  Emj.,  XXVI.,  040-70!),  1S!)6. 

'  W.  S.  (iresley,  "Traces  of  Organic  Remains  from  the  Huronian  (?) 
Series  at  Iron  Mountain,  IMich.,"  etc..  Trans.  A)iicr.  In.'<f.  Min.  Fii'J-, 
XXVI.,  527.  See  also  ^'c/t'ttcc,  April  24,  1890,  'J22;^»it'/'.  Geoluyist,  August, 
1890.  123. 

■>  T.  B.  Brooks,  Gcol.  Surrey  of  Wisconsin,  Vol.  III.,  4:50-06:3.  D.  H. 
Brown,  "Distribution  of  Phosphorus  in  the Ludington  Mine,"  M.  E..  XVI., 


THE  IRON  8EIiIES  CONTINUED. 


139 


Some  fiftoou  miles  north  of  the  Menominee  range,  and 
betweo^^  it  and  Negaunee  in  tlie  MaiMjuette  range,  is  a  narrow, 
closely  folded  syncdine,  called  the  Feleh  Mountain  district.  It 
contains  a  series  of  strata  closely  jjarallel  to  the  Lower  Menomi- 
nt'o,  and  apparently  an  outlier  cut  oil'  by  erosion.  If.  L. 
Smyth  has  alsv)  traced  out  hy  means  of  magnetic  observations 
a  northwesterly  extension  of  the  Menominee  range,  in  a  drift- 
covered  district,  so  as  almost  to  connect  with  the  Marcpiette 
area  west  of  the  Republic  trough.  From'^O  to  ;{()  miles  of  con- 
cealed rocks  have  thus  been  shown  that  may  prove  productive, 
although  the  ciieap  ores  of  the  Mesabi  range  have  made  their 
iininediate  future  uncertain.' 

2.02.34.  Example  Hr.  Penokee-Gogebic  District.  This  lies 
in  nn  east  and  west  range  of  hills  which  crosses  the  westerly 
boundary  of  the  Upper  Peninsuhi  and  Wisconsin,  and  is  from 
t'Mi  to  twenty  miles  south  of  Lake  Superior,  and  eighty  to  one 
liuudred  miles  west  of  the  Marijuette  mines.  The  rocks  are  less 
metamorphosed  than  in  the  previous  two  districts.  The  strata 
run  east  and  west  with  a  northerly  dip  of  ()()°  to  80°  (05°  in  the 
larger  mines),  and  with  no  subordinate  folds.  The  geological 
series  is  now  generally  called  the  Penokee,  following  the  usage 
of  Irving  and  Van  Hise,  to  whose  labors  we  owe  our  accurate 
kiiowle'Jge  of  the  district  and  from  whose  papers  the  following 
is  taken.  It  rests  upon  the  southern  complex  of  Archean  crys- 
tnlliues  and  forms  a  narrow  belt,  over  70  miles  long,  and  from 
lialf  a  mile  to  three  miles  broad.  The  geological  structure  and 
relations  are  much  simpler  than  in  the  other  districts,  and  have 
atTorded  the  key  for  the  solution  of  problems  elsewhere.  The 
strata  are  divided  into  an  upper  and  a  lower  series,  of  which ' 
the  former  is  much  the  larger  in  amount,  but  the  latter  is  the 


'"i  .1.  Fulton,  "  Mode  of  Deposition  of  the  Iron  Ores  of  the  Menominee 
\'im<ii',  :\Iiphigan."  Trnmi.  Amer.  Inst.  3fiii.  Eug.,  XVI..  .V^.").  N.  P.  Hiilst, 
"Tlie  (ieology  of  that  Portion  of  the  Menominee  Ran^e  East  of  the  Me- 
nominee River,  Proc.  Lake  Superior  Mining  Institute,  March,  1B93,  p.  19. 
P'M-  Lirsson,  "  The  Chapiu  Mine,"  Trana.  Amer.  Inst.  Min.  Eng.^XVl.. 
llil.  ('.  E.  Wright,  Geol.  Siirvcij  Wisconsin,  III.  ,0(i()-T:54.  (i.  H.  Williams, 
"  ^Ticenstone  Schist  Areas  of  the  Menominee  and  Marquette  Regions  of 
Michi^'an,  with  an  Introduct  "  by  R.  D.  Irving,"  Bull.  0:>,  U.  S.  Geol. 
Survey. 

'  H.  L.  Smyth,  ".Magnetic  Observations  in  Geological  Mapping."  Trans. 
4wi/-.  In.st.  Min.  Eng.,  XXVI.,  640,  189  6. 


i[ 


TUN  I  HON  Sh'Iilh'S  ('(tNTlNUlW. 


141 


nno  that  in  of  oronotnic   iinpurfnTico.     At  tlio   l);ise  is  a  cherty 
(ioloniltio  limestone  ;{(iii  IV^ut  aini  Iosh  tiiiok.     It  outcropH  cliietl}- 
at  tlio  extreme  west  and  the  extreme  eaHt.  and  has  no  immedi- 
ate connection  with  tlio  ores.     Over  tliis  lies  a  quartz-slate  or 
(|iiartzite  that  is   extrenud}'  persistent    throughout  tlie  entire 
area.     It  is  AOO  feet  and  less  thick.  !uid  forms  the  usual  foot- 
wall  of  tlio  large  ore   hodicis.     Al)ove  the  <|Uiirtz  slati*  is  the 
iron-hearing  nicmher.  sod  to  1,<)(K)  feet  thi(  k.      It  is  not  (dastic, 
hut  consists  of  chorty  carhonates  of  iron,  with  some  magnesium 
and  calcium,  or  of  derivatives  from  those  carhonates  and  cherls. 
Three  types  of  rt)ck  have  heen  estahlished  :  ( 1 )  The  slaty  and 
often  cherty  iron  carhonate,  more  or  less  analogous  to  siliceous 
iron  carl )onates  in  the  (*arhonit"erous  and  other  later  systems. 
It  is  regarded  as  of  organic  origin.     {'I)   Fei-ruginoiis  slates 
and  cherts.     The   iron  of  the  siderite  in  type  one  has  heen 
more  or  less  moved  and  redeposited  as  oxides,  and  rearrange- 
ment and  recrystallization  of  the  sili(!a  liave  also  transpired. 
(3)  Actinolite  and    magnetite   schists    have    resulted    hy  the 
change  of  nmch  of  the  iron  carbonate  to  magnetite  and  hy  the 
combination  of  the  remainder  with  lime,  magnesia  and   silica 
to  yield  actinolite.     This  last-named  type  is  especially  abun- 
dant west  of  Tyler's  Fork,  i.e.,  in  the  western  third  and  beyond 
the  productive  mining  region.     The  upper  Penokee  consists  of 
slate,  with   (piartzites.    graywackes    and    schists,    I'.'.soo    feet 
thick  and  less.     It  has  no  connection  with  the  ores,  and  is  suc- 
cei'ded  hy  the  Keweenawan  tra})s  and  sandstones  on  the  north. 
All  the  Penokee  strata  are  cut  hy  dikes  and  sheets  of  diabase, 
Home  of  which   in  the  iron-bearing  formation  have  plaj'ed  an 
iniiiDvtant  part  in  the  imxluctiou  of  the  ore  bodies. 

'i'lie  ores  are  found  in  the  lower  portion  of  the  iron-bearing 
inemlier,  and  either  on  or  near  the  underlying  (juartz-ahite. 
The  northerly  dipping  (luartz-slate  with  the  overlying  cherty 
carbonates  and  ferruginous  slates  is  cut  by  southerly  dipjiing 
diabase  dikes,  so  as  to  form  a  trough  with  sides  nearly  at  right 
angles,  The  troughs  themselves  pitch  doAvnward  to  the  west, 
and  in  them,  as  illustrateil  by  the  accompanying  figures  (Figs. 
•)2  and  Xi)  are  found  the  ore  bodies.  The  ores  are  soft  blue, 
brown  and  black  earthy  hematites,  and  often  contain  notable 
percentages  of  manganese.  There  is  little  doubt  that  they  have 
been  derived  from  the  cherty  carbonates  in  the  overlying  iron- 


aii 


112 


KEMP'S  ORE  DEPOSITS. 


*.     ■ 

.J 

iLl 

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< 

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O 

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"K 


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T~> 

"O 

1- 

> 

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z 
< 

b  > 
> 

ft 

oc 

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t; 

o 

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5 

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4 


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THE  IRON  SERIES  CONTINUED 


143 


5  i 


-  ^ 


..  i 


u 


bearing  foriimtion,  which  in  the  long  run  of  weathering  and 
erosion  has  yielded  its  iron  oxide  to  descendiui>;  atmospheric 
waters,  more  or  less  charj^ed  with  carbonic  acid.  The  iron- 
bearing  solutions  filtering  downward  have  come  to  comparative 
rest  in  the  troughs,  where  they  have  met  other  waters,  jjresumabh- 
obar^ed  with  oxygen.  Tiie  iron  oxide  has  heen  precipitated  and 
at  tbe  same  time  tlie  silica  has  been  removed  by  carbonated  waters 
or  by  those  which  have  been  rendered  alkaline  by  the  leaching  of 
tbe  neighboring  dikes.  The  latter  are  excessively  altered  and 
are  Ideally  called  soapstone  or  soap-rock  in  description  of  their 
comlilion.     It  is  impossible  to  state  how  much  of  the  Iron-bear- 


FlO   33. — Cronit-si'ction  of  the   Colby  mine,  Penokee-Gogehic  district ,  Mich- 

iijiin,  to  iUuxtrate  occurrences  ami  origin  of  the  ore.     After  V.  Ji. 

Vitn  Ilixe,  Anur.  Jour.  Sei.,  Janiuiri/,  1891. 

ing  formation  has  disappeared  in  the  protracted  process  of  super- 
ticial  erosion,  but  probably  some  thousands  of  feet.  The  depth 
to  which  the  ore  will  be  found  in  the  troughs  is  also  prcjblemati- 
cal.  It  is  now  known  to  extend  to  ^dO  feet  on  the  dip.  The 
solatioii  of  the  question  of  the  origin  of  tlicse  ores  has  been 
one  of  the  most  valuable  of  the  additions  to  our  knowledge  in 
recent  years,  and  has  proved  suggestive  and  fruitful  for  al'  the 
other  Lake  Superior  districts, 

The  range  became  productive  in  1885,  and  including  1807 
there  has  heen  sliipped  a  total  of  23,017,0'^3  tons  of  ore.^ 

t'-  31.  l<(ia,s,      Hoiiit^  Dik<>  Features  of  the  (Jojijebie  Iron  Kange,"  Trans. 
Amer.  Inst.  mn.  Emj.,  XXVII.,  550      R.  D.  Irving,  Geol.  Surrey  of  H  w- 


I 

I 


144 


KEMP'S  ORE  DEPOSITS. 


2.02.25.       Example    Orf.      Vermilion      Range,    Minnesota. 
Bodies  of  hard  s})ecular  ores  at  Vermilion  Lake,  and  soft  ores 
at  EI3',  deposited   in   troughs  as  in  the   preceding  examples, 
formed  hy  folded  or  intersecting  dikes,   which   penetrate  the 
iron-hearing   formation.      The   district   is   situated   in   north- 
eastern Minnesota,  and  lies  northwest  from  Lake  Superior.  Two 
Harbors,  the   shipping    point,   is    twenty-six    miles    east    of 
Duluth.  and  from  Tower,  the  principal  town  near  the  Vermil- 
ion Lake  mines,  it  is  sixty-seven  miles  to  the  docks.     Ely  is 
twenty-three  miles  northeast  of  Tower.       Leaving  the  lake  the 
railroad  first  crosses  with  heavy  grades  the  northwestern  flank 
of  the  Lake  Superior  synclinal,  chiefly  consisting  of  the  south- 
easterly dipi)ing  trap  sheets  of  the  Keweenawan.     Underlying 
the.se  is  a  series  of  gabbros  and  augite  sj'enites — the  former  of 
Avhich  contain  some  titaniferoiis  magnetites,  similar  to  those 
in  the  Adirondacks.     The  Mesabi  range  of  hills  succeeds  ou 
the  north,  but  although  ore-bearing  further  west,  as  described 
under  the  next  example,  it  is  barren  at  this  point,  and  consists 
chiefly  of  black  slates,  referred  to  the  Auimikie.     Sedimeii 
tary,  gneissic  and  eruj)tive  rocks,  regarded  as  Laurentiau  hy 
the  Minnesota  geologists,  succeed,  and  give  [ilace  finally  to  the 
metamorphic  rocks  of  the  Vermilion  range,  that  contain  the 
ore.     Still  further  north  are  the  Laurentian  rocks  again.    This 
whole  region  needs  further  and  very  detailed  map])ing  to  "crii- 
rately  bring  out  its  geological  structure,  although   the  niaiu 
points  mentioned  above  serve  to  outline  it.     The  immediate 
geological  relations  of  the  ores  have  been  elucidated,  however, 
b}'  the  recent  careful  work  of  H.  L.  Smyth  and  J.  R.  Fiulay, 

cousin.  III.,  pp.  100-107,  1880.     "Origin  of  the  Ferruginous  Schists  and 
iron  Ores  of  (lie  Lake  Superior  Region,"  Aiiicr.  Jour.  Sci.  iii..  XXXII., 
2H;],  iJOi");  see  ;ilso  under  Van  Ilise.     0.  I).  Lawton.  ••(ir()gel)icr  Iron  Klines." 
EiufuiccriiKj  iiiid  Muiiii</  Journal,  Jan    15,    lH<sr,  j).  42.     C.  R.  Van  Ilise. 
"On  tlie  Origin  of  tlie  "^'ica  Seliists  and  Blaek  Mica  Slates  of  the  Penukee- 
Gogebic  Iron-l>earing  SLiies,"  Aincr.  Jour.  Sci...  iii.,  XXXI.,  4r):!-^4r)9.    'The 
Iron  Ores  of   the   Penokee  Gogeliic  Series  in  ^Michigan  and  Wiscoii.sin," 
Amer.  Jour.  Sci..  iii.,  XXXVII.,  33.     Irving  and  Van  Ilise,  "The  I'eiiokti' 
Iron  bearing  Series  of   Nortiiern  Michigan  and  Wisconsin,"  JSlonoiivaph 
XJX..  U.  S.  (ii'ohxjicol  Stirrcji,  IS()2.     Rec.     An  abstract  of  t'le  nionouMiipli 
will  be  found  in  the  Triitli  Aiiinail  lii'p.  Director  U.  S.  Gcol.  Sorraj.  'M\ 
Rec.     C.   Whittlesey,    "The  Penokee  Mineral  Range,  Wisconsin,"  /Vw 
Host.   Soc.    Nut.    Ilinl..   IX.,   July,    IMCA     C.    E.    Wright,    Gcol.  Shrvrnvf 
Wisconsin,  III.,  pp.  2:59-301. 


I 


TUE  IRON  SERIES  CONTINUED. 


145 


fl.T  l^ingltuie  Weat  froiN  ';r«.vnwloh 'i'} 


Sink- of  Miles 

10      0      in  2I>  30  -10 

II    — '  I  I  I 

AMERICAN  qAf«K  NOTE  CO.|W.Y. 


Ili  l^ngltihlc  Woat  from  Wg^lihiston  IT' 


I'lu.  ;J4. — Map  of  the  MiimiKido  Iron  Riiikjck.     After  F.   11'.  Ueiiton,  'Jruns. 
Amer.  Ind   Aliu.  Euy.,  XXV 11.,  «J44. 


14C 


KEMP'S  CUE  DEPOSITS. 


to  which  the  subsequent  descrii)tion  is  chiefly  due.  For  a 
thorough  reading  up  upon  the  district,  the  references  given 
below  will  suffice.' 

The  Vermilion  Lake  mines  are  situated  on  the  top  of  an 
abrvipt  hill  above  the  town  of  Soudan.  Some  ore  appears  in 
Lee  Hill,  a  mile  or  two  southeast,  near  Tower,  but  the  depos- 
its are  not  known  to  be  large.  The  mines  at  Soudan  extend 
for  about  a  mile  along  a  main  belt  in  a  direction  a  little  north 
of  east,  and  upon  a  more  or  less  parallel  minor  belt  that  lies  ii 
short  distance  north.  This  alignment  is  due  to  the  intrusion 
of  a  great  mass  of  greenstone,  with  many  ramifying  dikes,  but 
all  on  this  general  line,  which  is  also  the  strike  of  the  jasper. 

On  the  northern  side  of  the  mines  the  surface  slopes  some- 
what sharply  to  Vermilion  Lake.  The  general  relations  arc 
illustrated  by  the  accompanying  Fig.  35.  Smyth  and  Fiiilay 
have  shown  that  stratigraphically  there  are  two  series  of  sedi- 
mentary rocks,  both  of  which  have  been  penetrated  by  abun- 
dant intrusions  of  quartz  porphyry  and  diabase.  The  lower 
series  consists  of  slates  and  graywackes,  not  excessively  meta- 
morphosed. The  slates  are  at  times  carbonaceous  and  occa- 
sionall}'  charged  with  pyrites.  Above  the  slates  lies  the  iron- 
bearing  formation,  consisting  of  (piartz,  variously  intermiufjled 
with  hematite  or  magnetite,  or  quite  free  from  either.     The 

'  A.  H.  Chester,  Eleventh  Avn.  Rep.  Minn.  Geol.  Survey,  155,  167.     T.  11 
Comstoi'k,  "  Ventiiiion  Lake  Distrift  in  liritisli  \\\wy\c\\"  Tmtis.  Aitur. 
luat.  Min.  Eirj.,  July,  18S7.     F.  VV   Denton,  "  Metlioils  of  Iron  Mini ii>^  in 
Northern  Minnesota,'  Idem,  XXVIl.,  844.     R.    D.  Irving,  Secentli  Ann. 
Rep.    U.  S.   Geo].  SKri-et/,  ts^.l-SO,   4:55.     H.  L.  Smyth  and  J.  R.  Fiiiliiy, 
"The  Geological  Structure  oi' the  Western  Part  of  the  Vermilion  Raiijic 
Minnesota."  Trans.  Amcr.   Inst.  Mhi.   Eikj.,  XXV.,   r)i».~)-(i4."),   1H!I."».     Kit. 
C.  R.  Van  Hise,  Bull.  tlU,  U.  S.  Geol.  Surrey.     Various  references  in  i-liap 
terii.     Bailey  Willi.s,  Teuff:  CVh.s.v.s,  XV.,  457.     Ale.xand.'i   Winclicll.  /■'//' 
tt'cnlh  AiDi.  R('2>-  Minn.  Geol.  Siirvei/,  174.     Also  "Some  Rcisultsof  Arclifiin 
Studies,"  Bull.  Geol.  Soc.  Amer.,  I,  357.    II.  V.  Winehell,  "Diaba,sic  Schists. 
Containingthc  JaspilytcBedsof  NortheastcrnMinnt'sota,"  Amcr.  Geol  .  11. 
18.     "The  Iron  Ranges  of  Minnesota."  Proc.  Lake  Su2>erior  Minintj  Insi. 
III.,  1895.  Rec.     N.  H.  Winehell:  Mai:y  references  to  the  region  by  X.  H. 
Winehell  are  to  be  found  in  the  reports  of  tlie  ^[inH.  Geol.  Surrey.     Tlicy 
are  practically   .svunniarized   in   the   next   reference.      N.   H.  a?id  II.  V. 
Winehell,  '•  The  Iron  Ores  of  Minnesota," /?/(//.   <!,  Geol.  Survei/  of  Mimi. 
Ree.     "On  a  Possible  Chemical  Origin   of  the  Iron  Ores  of  the  Kewiitin 
m  Minnesota,"  ^Imrr.  OVo/,,  IV,,    '.2!I1,  38!t.     "The  Tacoinc   Iron  Ores  of 
Minnesota  and  Western  New  England,"  Amer.  Geol.,  VI.,  203. 


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148 


KEMP'S  ORE  DEPOSITS. 


varieties  occur  in  parallel  but  narrow  bands,  never  over  three 
or   four  inches  across,   and  doubtless   represent  the    original 
beds  of  the  sediment,  but  just  what  the  character  of  the  origi- 
nal sediment  was,  whether  the  cherty  carbonates  of  the  south 
shore  or  the  probable  glauconites  of  the  Mesabi  range  is  ho])e- 
lessly    destroyed    bj'   metamorphism.     These  sediments  each 
form   three   belts,  as  shown   in   Fig.  35,  which   are   repeated 
because  of  sharply  compressed  and  pitching  folds.     After  the 
formation  of  the  sediments,  but  before  the  folding,  intrusions 
of  (juartz  porphyry  and  diabase  took  place,  as  dikes  and  slieets. 
some   large,  others   of   excessive   thinness.     Subse(]uently   all 
suffered  severely  from  compression.     A  larger  series  of  folds 
was  developed  along  an  east  and  west  line,  and  a  smaller  series 
at  right  angles  to  this.     This  severe  compression  and  sheariiij^t 
changed  the  (juartz  porphyries  in   large  part  to  conglomerate 
breccias,  and  to  sericite  schists,  while  the  diabases  passed  into 
chlorite  or  actinolite  schists   or  conglomerate  breccias.     Tiie 
breccias  first  resulting  from  the  crushing  have  had  their  frag- 
ments so  rubhed  upon  one  another  that  they  are  stretched  and 
rounded  and  have  their  interstices  hiled  with  sericite  schist  or 
chlorite  schist,  as  the  case  may  be.     The  brecciationtook  place 
on  the  anticlinal  ciests,  but  in  the  sj'nclinal  troughs  schists 
resulted.     These  foldings  also  formed  troughs  especially'  from 
the  corrugated  greenstone  dikes  and  from  the  intersections  of 
the  same,  and  Avhen  the  iron- bearing  formation  stood  over  such 
a  trough,  it  })assed  through  the  same  series  of  changes  tliat  liav^> 
been  earlier  outlined   mider  the  ^[ar(iuette  range,  so  that  the 
iron  oxide  became  concentrated  along  the  sides  and  on  the  bot- 
toms, while  the  silica  was  removed.     The  accom})anying  fig- 
ures exhibit  cross-sections   in   all   respects   like  those  on  the 
south  shore.     The  ores  are  all  hard,  dense,  specular,  and  are 
about  half  of  bessemer  and  half  of  noii-bessemer  grade. 

'lAVl.'!^').  The  geological  relations  at  Ely  are  practically  the 
same,  but  the  ore  body  as  disi)layed  in  the  Chandler  and  Pioufer 
mines  is  larger  than  at  Vermilion  Lake.  It  rests,  however,  on 
a  greenstone  dike,  which  is  folded  into  a  syncline  with  a  minor 
roll  in  the  bottom  of  the  trough  which,  as  shown  in  Fig.  "W, 
makes  it  a  doublo  one.  The  ores  are  soft  hematites  of  extraor- 
dinary richness  and  purity,  and  are  all  of  very  high  bessenier 
grade.     Indications  of  ore  are  strong  still  further  east,  and 


Fi 


I*,   -u. -Ope II   ciiljit   Miiuu'snfd   Iron   ('(iiiiiunn/'s  Mine,   S'lmlivi.    iiidi' 
Tower,  in  suiith  vicir  loukinfj  nr.st.     Pluitiiyrdjih  hi/  J.  F.  Kvnip.  ls!»4. 


tiS=:S^' 


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150 


KEMP'S  OJt/'J  DEPOSITS. 


devolojimontH  have  now  proved  iinpnrt;mt.  Tlio  combined 
output  of  the  iiiinoH  at  KI^vhikI  Vonniliou  I^ako  is  from  s(I(),(miu 
to  over  1, ()()(>,()(»()  tons  annually,  about  ('tjually  divided  between 
them.  The  total  hhipmont8  up  to  the  olo.se  of  18K7  have  been 
10,*!»S,71(;  tons. 

The  work  of  H.  L.  Smyth  and  Finlay  has  demonstrated  what 
maiiy  observers  have  felt  from  more  cursor)'  examination — 
that  the  f^(»ological  relations  of  these  ores  are  essentially  the 
same  as  those  on  the  south  shore.  Different  explanations  have, 
however,  been  advanced,  and  great  imcertainty  has  surrounded 
the  geology,  on  account  of  the  excessively  metamorphosed  and 


i'lu.  1(8. — Jlorizoiitid  and  luiiirni  rro.so-scctioiDioftht:  I'haudlir  ore  body  at  Ely, 

Minn.     After  Smi/th  ami  Finlay.  Trana.  Amer.  Inst.  Min. 

KiKj.,  XXV.,  5!ir.,  IS!),-.. 

obscure  igneous  rocks.  N.  H.  and  H.  V.  Winchell  have  argued 
that  the  ores  were  submarine  precipitates  from  volcanic  lapilli, 
furnished  by  submarine  eruptions.  From  the  lapilli  the  sea 
water  was  thought  to  have  extracted  the  iron  and  silica.  There 
seems,  however,  little  reason  to  (juestion  the  results  of  Smytb 
and  Finlay. 

3.03.37.  Example  Oe.  Mesabi  Range.  Of  much  more 
recent  development  than  the  other  districts  is  the  Mesabi 
range  of  Minnesota.  The  mines  began  to  make  important 
shipments  of  ore  in  1S0:5.  The  indications  are  that  the  depos- 
its are  not  less  extensive  than  those  in  any  other  of  the  Liilce 


77/ a;  iron  series  voyriNUED. 


161 


Siil«'ri<)r  localiticH,  and  tliat  they  aro  ov(>ii  lavf^'cr  and  of  acliar- 
iu'tt'r  to  I'o  nioro  easily  iniiicd.  'I'lic  im'snit  (hn-clopmcnts  arc? 
niliiatod  Houlhwi'st  of  Vcrinilioii  LaUe,  niid  iicart'i'  Diiliitli  and 
Lake  Su|teri(n'.  Tlioy  cover  a  wtrotch  of  about  .'JO  niileg,  from 
liiwabik  on  the  eaHt,  thronj^h  MoKinley,  Virginia,  Eveleth, 
]\l()iiiitain  Iron  and  smaller  towns  to  Hihi)in}^  on  the  west. 
Little  ore  is  known  beyond  Hibbinj^.  'Phe  fire  bodies  are  all 
south  of  tilt*  granit(»  ridj^e.  Tiie  ore  lies  nn(1or  the  blaek  slatt^s 
called  Auimikie  in  the  section  given  in  Paragra};'.!  ^.O'i/.Tt,  and 
over  the  (luartzite,  there  called  the  Pewabic;  but  they  are 
situated  twenty  miles  or  so  west  of  the  line  of  that  section.     The 


Fl«.  40. — (uiieral  evoHH-section  i>f  ore  holly  at  Biwuhik,  Mcsahi  Rdiif/f,  Minn. 
Aj'frr  II-   I".   Winc/icU,  Tweutiflh  Ann.  Hep.  Minn.  State  ileotoyid. 

010  Injdies  are  all  south  of  the  granite  ridge  called  the  Giants' 
Range.  Upon  the  southern  slo])es  of  this  range  lie  the  green 
schists  of  the  Keewatin,  which  are  unconformably  overlain  by 
tlio  Pewabic  quartzite.  On  this  rests  the  ore-bearing  rock, 
which  is  a  jaspery  or  cherty  siliceous  variety  call(!d  taconyte 
by  H.  V.  Wiuchell.  Over  this,  in  order,  come  greenish  siliceous 
slates  and  cherts,  black  slates  (referred  to  the  Auimikie),  and 
Ki'cat  masses  of  gabbro.  i)n  the  Hanks  of  the  Giants'  Range 
the  (lip  is  steep,  but  it  flattens  out  nearly  to  horizoutality  away 
from  the  granite.  All  the  foimations  above  the  Keewatin  are 
called  Tacouic  by  the  Wiuchells. 


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152 


KEMP'S  ORE  DEPOSITS. 


2.03.28.  The  ore  b'  Ties  lie  on  the  southerly  slopes  of  low 
hills,  and  are  found  immediately  below  the  mantle  of  glacial 
drift,  which  varies  up  to  200  feet  in  thickness.  Ore  indications 
ha\e  long  been  known  on  the  range,  and  various  reports  have 
been  made  in  former  years,  although  alwaj's  unfavorably.  The 
indications  then  available  showed  only  siliceous  limonites  of 
low  grade.  Deep  test  pits,  however,  which  penetrated  these 
caps  and  the  drift,  have  revealed  enormous  ore  bodies  and 
have  rewarded  persistent  prospecting.  The  ores  are  blue  aud 
brown  and  of  soft,  earthy  texture,  with  occasional  hard  streaks. 
They  lie  from  10  to  as  much  as  J  80  feet  below  the  surface  as 
now  mined,  and  where  the  stripping  is  sufficiently  thin  it  is 
removed  with  steam  shovels,  and  then  after  being  shaken  up 
Avith  black  powder  the  ore  is  excavated  in  the  same  way.  Tiie 
ore  bodies  are  lenses,  which  at  times,  as  at  the  Mesaba  Mountain 
or  Oliver  mine  in  Virginia,  appear  to  form  a  basin.  In  tlie 
central  part  of  this  mine  a  drill  hole  is  stated  to  have  shown 
335  feet  of  ore,  but  the  general  run  is  less.  The  ore  bodies  have 
usually  a  southeasterly  trend,  and  are  longer  thai  wide.  The 
blue  ores  are  richest  in  iron  and  purest  as  regards  phosphorns, 
and  they  are  the  ones  specially  desired.  Ores  for  foundry  iron 
also  occur  in  large  amount,  but  are  at  present  less  sought  for. 
The  rock  most  intimately  associated  with  them  all  is  the  chert. 
called  taconyte.  The  underlying  quartzite  is  occasionully 
shown  in  the  mines  as  well  as  the  overlying  slates,  but  the 
whole  region  is  so  completely  buried  in  drift  that  outcroppinp; 
rock  is  a  rare  thing. 

The  ores  are  thought  by  H.  V.  Winchell  to  have  originated 
bj'  replacement  of  the  taconyte.  The  rock  contains  calcareous 
streaks  which  have  perhaps  aided  in  furnishing  the  carbonic 
acid,  which,  it  is  thought,  has  dissolved  the  silica  of  the  taconyte 
in  the  replacement  process.  Recently,  valuable  observations 
on  the  geology  of  the  ores  have  been  accumulated  by  J.  E. 
Spurr,  while  in  the  field  for  the  Minnesota  Geological  Survey, 
in  whose  Bulletin  X.  the  detailed  report  has  appeared.  A 
preliminary  paper  in  the  American  Geologist  for  May,  18li4, 
gives  an  abstract  of  the  results.  As  in  the  Penokee-Gogebic 
and  Manjuette  districts,  the  western  end  of  the  Mesaha  range  is 
least  disturbed  and  metamorphosed.  The  stratigraphj' is  tim 
same  as  that  already-  outlined  in  preceding  paragraphs,  but  tlie 


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THE  IRON  SERIES  CONTINUED. 


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(|uartzite  is  simply  called  by  Spun*,  Aniinikie,  and  not  Pewa- 
liic.  The  iron-bearing  series  is  stated  to  be  from  500  to  1,000 
feet  thick,  with  an  average  of  SOO  feet.  The  unaltered  rock  is 
described  as  consisting  of  "cryptocrystalline,  chalcedonic  or 
finely  phenocrystalline  silica"  thickly  "strewn  with  rounded 
or  subangular  bodies  made  up  chiefly  of  a  green  mineral," 
rejj;arded  as  glauconite,  the  hydrated  silicate  of  protoxide  of 
iron  and  potash.  Analyses  of  the  rock  corroborate  this  deter- 
mination, because  thej'  indicate  a  constant  but  small  percent- 
aj,'o  of  potash.  Layers  of  the  rock,  rich  in  calcite  (probably 
magnesian)  also  occur.  Spm-r  is  thus  led  to  regard  the  rock  as 
an  altered  greensand,  to  which  view  similar  conclusions  regard- 
ing the  much  more  recent  and  unmetamorphosed  ores  of  Texas 
and  Louisiana  (see  2.01.15)  give  support.  The  chemistr}'  of 
the  deposition  is  considered  by  Spurr  to  be  the  following: 
Atmospheric  waters,  with  dissolved  carbonic  acid,  and  some 
alkaline  salts  have  filtered  into  the  cracks  and  become  diarged 
with  ferrous  carbonate,  where  the  conditions  prevented  oxidation. 
The  greater  solubility  of  the  ferrous  siilt  led  to  its  solution 
before  the  alkali  attacked  the  silica. 

Later,  reaching  more  open  and  fissured  portions,  the  ferrous 
salt  was  oxidized  and  deposited,  while  the  silica  was  attacked 
and  removed  by  the  alkali.  In  time,  thus  the  iron  oxide  was 
concentrated  along  fissured  strips,  near  faults,  and  the  like, 
whereas  the  silica  was  removed.  It  is  recognized  as  well  that 
the  ferrous  salt  was  precipitated  as  carbonate,  amid  deoxidiz- 
ing conditions.  The  change  from  silicate  or  carbonate  to 
liydrous  oxkle  of  iron  led  to  shrinkage  and  shattering,  and  the 
passage  from  hydrous  oxide  to  carbonate,  where  such  occurred, 
to  expansion  and  shattering.  It  follows  from  the  explanation 
that  the  regions  of  rich  ore  bodies  would  be  those  of  notable 
geological  disturbances,  so  that  faults  are  presumed  near  Vir- 
ginia, Biwabik  and  elsewhere.' 

'  C.  E.  Bailey,  "Mining  Methods  on  the  Mesahi  Range,"  Trans.  Amcr. 
/».st  Mill.  Eng.,  XXVII.,  529.  F.  W.  Denton,  "Open  pit  Mining  with 
Special  Reference  to  the  Mesabi,"  Proc.  Lake  Superior  Mining  Inst.,  III., 
l^^iN).  '  Jlethods  of  Iron  Mining  in  Northern  Minnesota,"  Trann.  Amcr. 
Inst.  Mi„.  Eng.,  XXVII.,  344.  E.  P.  Jennings,  "TheMesabi  Range,"  Sci- 
ence, XXIII.,  78.  E.  J.  Longyear,  "Explorations  on  tlie  Mesabi  Range," 
Tra)is.  Amer.  Inst.  Min.  Eng.,  XXVII..   mi.     J.  E.  Spurr,  "TheMesabi 


11 


IWl  "I- 


154 


KEMP'S  ORE  DEPOSITS. 


!;>.03.1^'.>.  Hematites  apparently  much  like  those  of  Lake 
Superior  have  been  reported  from  the  Hartville  iron  district  iji 
Laramie  County,  Wyoming.  The  ores,  according  tc  W.  C. 
Knight,  constitute  irregular  zones  in  Carboniferous  rocks  and  are 
associated  in  many  cases  with  copper  deposits.  (See  2.04.^8.) 
The  published  analyses  show  rich  ores  of  bessemer  grade.' 

'Z.yyl.'Ml  The  explorations  of  Mr.  A,  P.  Low,  of  the  Geologi- 
cal Survey  of  Canada,  have  shown  extensive  developments  of 
iron  carbonates,  and  magnetite  and  hematite,  associated  witji 
jasper,  and  with  cherty  carbonate  of  lime,  along  the  east  side  of 
Hiaisoii  Ba.y,  and  in  the  valleys  of  the  Koksoak  (called  also 
L'ugava)  and  Hamilton  rivers.  Mr.  Low  describes  tiie  enclos- 
ing strata  as  Cambrian.  The  samples  bronglit  back  proved 
I'.ither  low  in  iron  {'-W  to  h\%  Fe).  but  the  geological  relations 
are  extraordinarily  like  those  of  Lake  Superior.'"' 

•^.O'^.iU.  Example  10.  Jame«  River,  Virginia.  Specular 
iiematite  in  narrow  beds  (lenses),  interstratified  with  (piartzites 
and  slates  of  metamorphic  character  and  Archean  age.  They 
run  four  to  six  feet,  or  less,  in  thickness,  with  prevailingly 
vertical  dip,  but  they  also  pitch  diagonally  down  on  the  dip 
like  the  lenses  of  magnetite,  later  described.  They  furnish  a 
very  excellent  grade  of  ore.  The  ore  bodies  are  found  along 
both  sides  of  the  James  River,  a  few  miles  above  Lynchburg. 
Some  magnetite  also  occurs  in  the  ragion,  and  some  limonite. 
More  or  less  clay  accompanies  the  ore.* 


Irou-bearing  Rocks,"  Bulletin  10,  Minn.  Geol.  Survey.  1894.  Rec.  ' '  The  Iron 
Ores  of  tlie  Mesahi  RuiiKe,  '  Amcr.  Geologint,  XIII.,  May,  1894.  3:^..  11.  V. 
Wiiiehell,  Tu-ciitieth  Ann.  Rep.  Minn.  State  Geol,  113,  1892.  "Iron  Ores 
of  Minnesota,"  Bull.  G,  Minn.  Geol,  Survey.  H.  V.  Winoliell  and  J.  T. 
Jones.  "The  Biwabik  IMine,"  Trans.  Amer.  Just.  Miii.  Eiuj.,  XXI..  951. 
For  an  eiirly  account  of  theMesabi  Range  see  New  York  Times,  December 
11.  189-J. 

'  W.  C.  Knight,  Bulletin  14,  Wyoming  Experiment  Station,  Laramie, 
Wye,  pp.  1:5.")  and  170.  A  large  series  of  analyses  apnears  in  the  prospec- 
tus of  the  Wyoming  Railway  and  Iron  Co.  E.  P.  Snow,  "The  Hartville 
Iron  Ore  Deposits  in  Wyoming,"  Engineering  and  Mining  Journal,  Octo- 
ber .").  1S9."),  p.  ;]2(). 

^  Tlie  above  note  is  due  to  the  courtesy  of  Dr.  George  M.  Dawson,  Di- 
rector of  the  Geological  Survey  of  Canada,  who  kindly  gave,  the  writer 
an  abstract  of  Mr.  Low's  rejjort  in  advance  of  its  publication. 

'  E.  B.  Benton,  Tenth  Census,  Vol.  XL,  p.  3(i8  (on  Virginia).  J.  L. 
Campbell,  Geology  and  Resources  of  the  James  River  Valley,  p.  49,  New 


rilE  IRON  SERIES  CONTINUED. 


155 


•^.0'-i.3'^.  Similar  lenses  of  HpecuUir  ore  and  ningnetite  are 
found  in  central  North  Carolina,  in  schistose  rocks,  which 
have  been  referred  to  the  Hurouian. 

As  stated  under  •i.(f2.'^*li,  lenses  of  specular  hematite  of  very 
excellent  (juality  are  found  also  in  metamorphic  rocks,  north 
of  Fort  Laramie,  Wyoming,  which  may  prove  productive  in  time. 
■2. 02, IK}.     Example  11.     Pilot  Knob,  Missouri.     Two  beds  of 
liiud  specular  hematite  separated   by  a  thin  seam  of  so-called 
!?late  (possibly  volcanic  tuft"),  and   intjrstratified  with  breccias 
and  sheets  of  porphyry.     Along  the  eastern  limit  of  the  Ozark 
uplift  of  Missouri  and   Arkansas  a  series  of  knobs   of  granite 
autl  [lorpbyritic  rocks  project  through  the  Cambrian  limestones 
and    sandstones.      They   are   older  than    the   limestones,  and 
clearly  were  not  intruded  through  them.     The  limestones  and 
sandstones  lie   up  against  the  porphyry  and    in   the  valleys 
between.     The  imderlying  porphyry  has  been  found  in  the  val- 
ley near  Pilot  Knob,  after   penetrating  four   hundred   feet  of 
sedimentary  rocks.     The  porphyry  uid  ores  have  often  been 
cab  id  Huronian,  but  in  view  of  the  recent  reorganization  of  the 
Huronian  (see  Example  !)),  this  is  not  done,  nor  ever  has  been, 
on  any  accurate  grounds.     Pilot  Knob  is  formed   by  one  of 
these  eruptive  knobs.     It  consists  of  sheets  of  ]K)r])hyries  that 
are  capped  by  porphyry  breccia,  and  two  ore  beds,  and  the  in- 
tervening slaty  rock  which  may  be  a  tuft'.     The  beds  strike  and 
(lip  i;j°  8.  S.  W.     The  hill  is  over  (iOO  feet  high.     The  lower 
bed  has  furnished  most  of  the  ore,  running  from  '^5  to  40  feet 
thick,  and  afl"ording  a  dense  bluish,  specular  hematite  of  from 
(A)  to  00%  Fe,  siliceous  and  ver}'  low  in  phosphorus.      The 
iijtper  bed  is  irregular  and  of  lower  grade,  and  runs  from  G 
to  10  feet  thick.     The  Pilot  Knob  mines  in  this  solid  ore  are 
now  substantially  exhausted. 

Kecent  drill  holes  on  the  northerly  slope  and  below  the  out- 
cropping face  of  ore  have  shown  that  under  the  Cambrian 
strata  of  the  valley  there  is  a  great  bed  of  ore  boulders  or 
breccia  in  clay,  much  as  is  the  case  at  Iron  Mountain,  later 
described.     Analyses  of  these  latter  ores  were  not,  however, 

York.  lf^82.  H.  B.  C.  Nitze,  "On  North  Carolina,"  Bulletin  No.  1,  North 
Curolimt  (Jeol.  Survey,  IH'ja.  B.  Willis,  Tenth  Census,  Vol.  XV.,  p.  301. 
The  Virginias,  a  monthly,  formerly  published  by  Jed.  llotchkiss,  at  Staun- 
ton, contains  much  information  on  Virginia  in  general. 


I  ^  I.I 


n  ji 


■i  ■'   \ 


'Rffff^?*^?. 


Oi 

si- 


e  ', 


>  :S  S 


J?  e 


^  'M 


k- 


TUE  IRON  SEIilES  CONTINUED. 


157 


(sufficiently  encouraging  for  development  during  the  recent  low 
piicea  for  iron.  Doubtless  the  bed  will  afford  important  re- 
.serves. 

•^.0'^.l}4.  Near  Pilot  Knob  are  two  other  hills  of  porphyry, 
Shepherd  Mountain  and  Cedar  Mountain,  whose  ores  are 
structurally  more  related  to  Example  11 «.  The  first  contains 
tlu-ee  veins,  the  Champion,  the  North,  and  the  South.  They 
are  long  and  narrow  (4  to  10  feet)  strike  north  ()()°  to  70°  east, 
and  dip  70°  north.  The  Champion  vein  contained  a  little 
streak  of  natural  lodestone,  but  the  ore  is  mostly  specular. 

The  North  vein  shows  a  good  breast  of  ore  five  feet  wide, 
but  too  full  of  pyrite  to  be  available.  Cedar  Mountain  has  a 
vein  of  specular  ore.  Neither  hill  has  been  an  important  pro- 
ducer. Minor  veins  have  been  foimd  on  neighboring  porphyry 
hills  (Buford,  Hogan,  and  Lewis  mountains),  some  of  which 
contain  mucli  manganese. 

"i.d-^.oo.  Example  11a.  Iron  Mountain,  Missouri.  Veins 
of  hard,  specular  hematite  irregularly  seaming  a  knob  of  por- 
phyry. Iron  Mountain  is  five  or  six  miles  north  of  Pilot  Knob, 
and  is  a  low  hill  with  a  westerly  spur  called  Little  Mountain. 
It  has  also  a.  northerly  spur.  It  consists  of  feldspar  porj)hy- 
ries,  more,  or  less  altered.  These  are  seamed  with  one  large, 
and  on  the  west  somewhat  dome-shaped,  parent  mass  of  ore  and 
innumerable  minor  veins  that  radiate  into  the  surrounding 
rock.  Upon  the  fimks  of  the  porph3'r3'  hill  rests  a  mantling 
succession  of  sedimentary  rocks,  that  dip  av'ay  on  all  sides. 
The  lowest  member  is  a  conglomerate  of  ore  fragments,  weath- 
ered porphyry,  and  residual  clay  left  by  its  alteration.  It  is 
re<,'arded  by  Pmnpellyas  formed  by  pre-Silurian,  surface  disin- 
tegration and  not  bj'  shore  action,  inasnmch  as  sand  does  not 
till  tlie  interstices,  while  white  clay  from  decomposed  porphyry 
<loes.  It  is,  however,  overlain  by  a  thin  bed  of  coarse,  friable 
sandstone,  which  marks  the  advance  of  the  sea,  and  whose 
tnnnation  preceded  the  limestones.  This  conglomerate  was  in 
later  years  the  principal  source  of  the  ore,  but  the  mines  are 
now  considered  to  be  worked  out.  It  was  mined  underground, 
hoisted  and  washed  by  hydraulic  methods,  like  those  employed 
in  the  auriferous  gravels  of  California,  and  then  jigged.  The 
apatite  has  largely  weathered  out  of  it.  The  rock  of  the 
mountain  itself,  in  the  cuts  of  the  mines,  is  largely  kaolinized, 


\fiH 


KHMI'S  0/.7-;  /)/'JI'(JS/'rs. 


and  exhibits  everywhere  the  effects  of  extreme  alteration.  The 
Hnialler  veins  that  penetrate  the  porphyry  show  at  times  easts 
or  mucli  altered  cores  of  a})atile  crystals. 

'^.()2.;i<i.     The   porphyries  of    Pilot   Knob  and   Iron   Jfonn- 
tain,  in  thin  section,  are  seen  to  belong  to  quartz  porpliyri(;s. 
ft'ldspar  porphyries,  and    porphyrites.      Both    orthoclase    and 
plagioclase  are  present  in  them,  and  many  interesting  forms  of 
structure.     One  significant  fact  is  that  they  are  everywhere 
filled  with  dusty  particles  of  iron  oxide,  probably  magnetite. 
An  eruptive  origin  Avas  originally  assigned  to  these  ores  by  J. 
]).  AVhitney  {Mrtdllic.  Wcd/f/i  of  the   CiiUcil  Sfafcs,  p.  -Kit, 
IS")-!:),  just  as  to  the  Lake  Superior  hematites.     The  later  in- 
vestigfitions  of  Adolph   Schmidt  for  the   Missouri  Survey   in 
1871  arrived  at  a  different  conclusion.     Dr.  Schmidt  considered 
them,  wh(>ther  occurring  in  an  apparent  bed,  as  at  Pilot  Knob, 
or  in  various  more  or  less  irregular  veins,  as  at  Iron  Mountain, 
to  have  been  formed  either  by  a  replacement  of  the  porphyries 
with   iron   oxide  deposited  from  solution,  or  by  a  filling  in  the 
same  way  of  fissures,  probably  formed  b}'  the  contraction  of  the 
porphyry  in  cooling.    In  the  valuable  report  on  iron  ores  by  F. 
L.  Nason  in  the  Missoin-i  (rcoloi/ica/  Siirr<\i/  a  sedimentary 
origin  is  advocated  for  the  Pilot  Knob  beds.     Thej'  are  con- 
ceived to  have  been  deposited  in  a  body  of  water  in  a  hollow, 
between  formerl.y  existing  porphj-ry  hills,   which  rose  above. 
In  the  course  of  weathering,  the  hills  became  the  valleys,  and 
the  early  sedimentary  beds  the  hilltop,     It  is,  however,  some- 
what difficult  to  understand  how  the  more  or  less  incohoient 
sediments  withstood   degradation  better  than  the  hard,  firm, 
porphyry  hills.     Some  such  origin  as  sedimentation  or  replace- 
ment is,  however,  the  only  reasonable  one.     It  is  not  improba- 
ble that  the  Pilot  Knob  ores  originated  in  the  saturation  Hud 
more  or  less  complete  replacement  of  layers  of  tufts  with  in- 
filtrating iron  oxide. 

An  extended  table  of  analyses  of  Iron   Mountain  ores  will 
be  found  in  Mineral  Resources  of  the  United  States,  1881t-00, 


1 1**  1 


■^^ 


>  G.  C.  Broailhead,  "The  Geological  History  of  the  Ozark  \J])li{t,"Amer. 
Oeol,  III.,  6.  J.  R.  Gage,  "On  the  Occurrence  of  Iron  Ores  in  Missouri," 
Trans.  St.  Louis  Acad.  Sci.,  1873,  Vol.  III.,  p.  181.  E.  Harrison,  "  Ageof 
the  Porphyry   Hills,   Ibid.,  Vol.   II.,  p.  004.     E.   Ilaworth,  "A  Coutribu- 


i 


ove 


■^    ^y  1."- 


''''»»-u»   - 


^;:^ 


Fi(i  4:'.. —  Vh'w  of  open  citt  at  Pilot  Knob.  Mo.,  shoirlufj  the  bedded  ehar- 
(icfir  (if  tJic  iron  ore.     From  ((  plmtiK/riiiili  hij  ,!.  F.  Kcnij).  1888. 


■;i»;h; 


f^^^^ 


"^ 


u^ 


riih:  liio.y  sfjuhs  coNTLM'h'n. 


ir)0 


ANAIiYHKH  OK   HKM.ATITKH.    KKD   AND  HPKCULAR. 

(T!i«  Hiiinn  (liHcriiiiiiiatidii  iriiiMt,  ln«  <'iii|)i(iy('<l  in  looking;  ovor  tlioso  anal- 
VHiiH  tliiit  WHS  t!ni|»liasizt'(i  under  linionitc  ) 


Fe. 

44,10 
51.75 
44.40 
5l.(i:j 
•')((,  40 

P. 

0.050 
I.IIDV* 
0.115 
0,;i45 

s. 
o.3ao 

SiO,. 

fi.45 

ii,o. 

Clinton,  N.  Y.  (fossil  ore) 

Wisconsin  (fossil  oie) 

Pcnnsyiviiniii  (.MilUin  ore) 

Tcimcsset'  (Mimk-s  (ounty) 

Itirti  1  i  iifli.'ii  1 1       A  IlL 

12. «« 

3.77 

0.03H 

0.iJ40 
O.H,s;{ 
(t.0S5 
(t,5;!0 
0.007 
0.000 
0.(t4() 
0.015 
0.1  :U) 

(i.Olll 

lO.HO 

0.50 

A 1 1 1  w  ( ' ri t    X    Y    

40.  :W 
511.41 
OS.  10 
(14.m:{ 
00.47 
(i5..5(» 
51).  15 
40.8!) 
01. HI 
70.00 

Missiiiiri  (CniAvfonl  County) 

Miinint'tt*!  (list.,  Miirii.   (siK-cular) 

Menoniini'o  district,  Michigan.  . . 

Iidu  Mountain,  Mo 

Pilot  Knob,  Mo 

.limit's  River  (Maud  vein) 

Kliij, 

'  "'i.bV 

8.00 

8.;{,M 

5.75 

ia.37 

3.03 
3.19" 

0.030 

(i.l70 

5.07 

8.47 

I'lirc  niinHrui 

These  aualyses  are  mostly  taken  from  Sttito  reports  and  from 
Miiicntl  Re.soiif'cs  of  tlm  United  Slates.  Tliey  are  intended 
to  illustrate  he  general  run  of  C()ni{)ositions,  bnt  for  Birmiiig- 
liaiu  and  Marcjnette  are  high.     Analyses  vary  widely. 

tiou  to  the  Arcliwan  Geology  of  Missouri,"  Atner.  Ucul.,  I.,  380-808;  "Age 
and  Ori>;in  of  the  Crystalline  Rocks  of  Missouri,"  Bull.  f>.  Mo.  Geol.  Sur- 
ny,  l.S'.M.  A.  V.  Lconiiard,  "Notes  on  the  Mineralogy  of  iMissouri," 
Trans.  St.  Luuis  Acad.  ISci.,  Vol.  IV.,  j>.  440.  F.  L.  Nason,  "  Ue])ort  on 
till'  Iron  Ores  of  Mis.souri,"  Mo.  Ucol.  Siirni/.  II.  Rec.  R.  Puini)elly, 
"Ueology  of  Pilot  Knob  and  Vicinity,  '  Mo.  Ucol.  Surrey,  \H72,  p.  5;  see 
also  remarks  on  Iron  Mountain,  Jitill.  (ivol.  Soc.  .liiivr.,  Vol.  II..  p.  2"J0. 
Rec.  W.  B.  Potter,  "The  Iron  Ore  Regions  of  Missouri,  '  ./(>»/•*(<//  U.  S. 
As.s(t.  Chitrcoiil  Iron  Workers,  Vol.  VI.,  p.  38.  Rec.  F.  A.  Sampson,  "A 
Biliiiography  of  tiie  (Jeology  of  Missouri,"  Bitli  .'.Mo.  (Icol.  Siirri'i/,  1800. 
(This  is  a  valnalile  book  of  reference.)  F.  Shepherd.  Ami.  liep.  Mo.  (nol. 
Siirrrif,  18.58-.54.  Hi.st.  A.  Schmidt,  "Iron  Ores  of  Mis.souri,  '  il/o.  (feol. 
Sinni/,  1873,  j).  45,  and  especially  p.  94.  Rec.  J.  I).  Whitney.  MrtolUc, 
W'idltli  of  the  r.  S.,  p.  4;!(.  »)f  more  recent  issues  are  the  following; 
E.  Haworth,  "The  Crystalline  Rocks  of  Missouri,"  ii,'/;////// .fl»i(.  liej).  Mo. 
<!i-i)l.  .S'^crc//,  18114,  p.  81.  C.  R.  Keyes.  "(ieographic  Kelatioiis  of  tlie 
(huiiilesaud  Porjihyries  in  the  Eastern  Part  of  the  Ozarks,"  iy^//.  dcol. 
Soc.  Amcr.,  VII.,  ;U)8,  1800.  "  Report  on  the  Mine  la  Motte  Sheet,"  Geol. 
Siirnii'df  Mo.,  IX.,  .Sheet  Report  4.  Arthur  Winslow,  E.  Haworth  and 
V.  L.  Nason,  'ReiH)rt  on  the  Iron  INIountain  .Sheet,  '  Idem,  Sheet  Report 
3.  Ror.  This  last  is  the  best  work  of  reference  as  regards  the  mines. 
Further  details  will  be  found  in  VVinslow's  Bulletin  183  of  the  U.  S.  GeoL 
Surccii.  uti   'The  Disseminated  I.ead  Ores  of  Southeastern  Missoiu'i." 


CHAPTER  III. 


MAGNETITE   AND   PYRITE. 

3.03.01.  Example  12.  Magnetite  Beds.  Beds  of  magne- 
tite, often  of  lenticular  shape,  interfoliated  with  Archean 
gneisses  and  crystalline  limestones.  They  are  extensively 
developed  in  the  Adirondacks,  in  the  New  York  and  New  Jer- 
sey Highlands,  and  in  western  North  Carolina.  The  presence 
of  magnetite  in  Michigan  (Example  9a),  in  Minnesota  (Exam- 
ple (>b),  on  Shepherd  Mountain  in  Missouri  (Example  11),  and 
in  Virginia  (Example  I'Z)  has  already  heen  referred  to.  Other 
magnetite  bodies  are  known  in  Colorado,  Utah,  California  ami 
Wyoming,  and  will  be  mentioned  subsequently.  Titanium  is 
often  present,  but  the  titaniferous  ores  are  made  a  special  exam- 
ple. The  same  is  true  of  pyrite  and  pyrrhotite.  Apatite  is 
always  found,  although  it  may  be  in  very  sma^l  quantity. 
Chlorite,  hornblende,  augite,  epidote,  quartz,  feldspar,  and  a 
little  calcite  are  the  common  associated  minerals.  In  New 
Jersey  the  beds  occur  in  several  parallel  ranges  or  belts. 

"2.0;?. 02.     Exaivple    12a.      The   Adirondacks.      Deposits  of 
magnetite  are  extensively  developed  in  the  cr3'stalline  area  of 
the  Adirondacks,  and  they  show  some  interesting  relationships 
between  the  character  of  the  ore  and  the  nature  of  the  country 
rock.     The  titaniferous  varieties  to  be  later  described  favor  the 
interior,  mountainous  core,  but  the  nontitaniferous  are  especially 
foimd  on  the  flanks  and  in  the  foothills.    The  region  is  in  large 
part  an  eruptive  area  of  plntonic  rocks  representing  various 
members  of  the  great  gabbro  famil}^  whose  chief  minerals  are 
labradorite  and  some  form  of  pyroxene.     There  are  members 
which  are  little  else  than  labradorite  and  which  are  called 
anorthosites;  there  are  others  containing  labradorite  and  liyper- 
sthene,  the  norites;  still  others  are  dark  and  basic,  and  cousist 


MAGNETITE  AND  PYRJTK 


161 


of  little  else  than  labradorite,  augite,  hypersthene,  ilmenite 
an<l  garnets,  the  last-named  having  been  formed  by  metamor- 
phism/  Angite  syenites  of  massive  charactei*  have  recently 
been  recognized  by  H.  P,  Gushing,  and  the  discovery  has 
thrown  much  light  on  many  rocks  only  known  before  as 
gueisses.  All  these  eruptives  have  suffered  greatly  from  dj-na- 
niic  nietamorj)hism,  and  are  now  as  a  rule  decidedly  gneissoid 
iu  structure.  In  addition  to  the  eruptives  there  are  white,  crys- 
talline, graphitic  marbles,  usually  charged  \vith  pyroxenes; 
black,  horublendic  schists;  quartzites;  and  quartzose  gneisses 
tbat  represent  a  series  of  sedimentary  rocks  of  Algoukian 
age,  but  that  are  now  much  broken  by  the  eruptives  above 
nieutioned.  The  Algonkiau  sediments  are  most  satisfactorily 
exhibited  on  the  Avesteru  side  of  the  mountains. 


'  TliH  general  geology  of  the  Ailirondacks  is  described  by  E.  Emmons  in 
Ills  "Report  on  the  Second  District  of  New  York,"  N.  Y.  Ndtnral  Hintory 
Snnri/,  1H43.  Tlie  later  i)aiH'rs  of  iinponance  are  tlie  folknvnig.  and  a 
{general  review  of  work  that  liad  been  done  up  to  1892  is  given  by  J.  F. 
Kemp,  '•  A  Review  of  Work  Hitherto  Done  on  the  Geology  of  the  Adiron- 
<lacks,''  7V(//(.s.  N.  Y.  Aciid.  of  Sciences,  XII.,  19,  1892.  H.  P.  Cnshing,  "Re- 
port oil  tin.'  Geology  of  Clinton  Co.,"  L-'tli  Aim.  liej).  State  O'eohxjint,  1893, 
4^3;  h'ltit  lileiH,  499.  "Report  on  the  Boiuulary  Between  the  Potsdam  and 
Pre-Cambiiiui  Rocks  North  of  the  Adirondacks,"  10t]i  AiiniKtl  Report 
State  Gcvloi)int.  189(5.  An  additional  report  on  Franklin  C(j.  is  in  pre.ss 
(1899).  "Aiigite-syenite 'iiieiss  near  Loon  Lake.  N.  Y.,"  Bull.  Geol.  Soc. 
Ainei:,  X.,  lTT-192.  J.  F.  Kemp,  "  Gabbros  on  the  Western  Shore  of  Lake 
Cliiiniplaiii,"  /(/('/)/,  v.,  2i:i,  1894.  "("rystaUine  Limestones,  Opliicalcites 
and  Associated  Schists  of  tbe  Eastern  Adirondack.s,"  Idem,  VI.,  241.  "Pre- 
liminary Report  on  the  Geology  o"  Essex  Co.,"  Rep.  N.  Y.  State  Geologist 
forls9;5,  79,  1W)4;  cojitiiuied  in  the  J.'dh  Ann.  Rep..  Tdem.  18fl.Ti,  .^,7').  A 
reiioit  on  Warren  Co.  is  in  pres.s.  "The  Ceology  of  ^loriah  and  Westport 
Townsliips.  Essex  Co.,"  Bull.  N.  Y.  State  Museum,  III.,  825,  189o.  "Tlie 
(lfi)liiu;y  of  tlu'  Magnetites  near  Port  Henry,  N.  Y.,  Tntns.  Amev.  Li.nt. 
Mill  Eiuj.,  XXVII.,  140,  1897.  •  TlietJeology  of  the  Lake  Placid  Region," 
IMl.  X.  Y.  State  Museum,  V.,  51,  1898.  C.  H.  Smyth,  Jr.,  "A Geological 
Kt('()iiii()is.saiice  ill  the  Vicinity  of  Gouvernenr,  N.  Y.,  Trans.  N.  Y.  Acad. 
»SV/..  XII..  203,  189;}.  "  Petrograpliy  of  tiie  Gnei.sses  of  tlie  Town  of  Gonv- 
enieiir.  N.  Y., "/</<>/«,  XII.,  20:i.  189:5.  "  Report  on  the  Geology  of  V,mr 
Townships  in  St.  Lawrence  and  Jefferson  Counties,"  IJth  Auii.  Rep. 
^.  ) .  S((de  Geolixji.^t.  491.  ■Crystalline  Limestones  ami  Associated  Rocks 
of  tl'.eXditliwesteni  Adirondack  Region,"'  Bull.  Geol.  St.^.  Amer.,  VI.,  2«i;i, 
1S95  •'  Hejiort  on  the  Crystalline  Rocks  of  St.  Lawrence  Co.,"  15th  Ann. 
Ji'P.  X.  v.  State  Geoloijist,  1895,  477.  Additional  rejiorts  on  the  western 
Adiroiuhirks  are  in  jji-ess. 


.    I 


I     ' 


1C2 


KEMP'S  out:  DEPOSITS. 


3.03.03.  The  magnetites  are  found  in  the  form  of  lenticular 
masses  that  correspond  perfectly  to  the  foliation  of  the  gneisses. 
They  may  extend  long  distances  on  the  strike,  as  at  Lyou 
Mountain,  where  tiie  Chateaugay  ore  is  said  to  be  traceable 
four  or  five  miles,  but  it  is  lean  over  most  of  the  distance.  Belts 
more  or  less  continuous  for  a  mile  are  opened  up  in  several 
places.  The  ore  may  be  in  gneiss  that  is  pracitically  (juartz 
and  microperthite  as  at  Hammondville;  or  in  pj'roxenic  gneisses 
as  at  Lj'on  Mountain ;  or  on  the  contact  of  gneiss  like  that 
v^^hich  forms  the  wall-rock  at  Hammondville  just  mentioned, 
and  dark,  basic,  hornblendic  gneiss,  derived  from  intruded 
gabbro;  or  on  the  contact  of  gabbro  like  the  last  and  gneisses 
w^hich  are  involved  with  crystalline  limestones,  as  at  the  Cbec- 
ver  mine;  or  finall}',  in  the  crystalline  limestones  near  gabljio 
intrusions,  as  at  the  Weston  mines,  Keene  Center.     The  ores  at 


1 

^ 

up'* 

n 

1 

N.  60    70  E. 


liOOFeel 

Fig.  47. — Cross-section  of  the  Cheever  iron,  mine,  near  Port  Henry,  N.  Y., 

showina  the  occurrence  of  the  ore  in  pi/roxene  yneinx,  jiint  over  gahhro. 

Lake  Champldin  terimnnt.cs  the  section  at  the  riyht.     After 

J.  F.  Kemp,  Bull.  N.  Y.  State  Museum,  Vol.  Ill,  p.  346. 

Mineville  have  been  regarded  as  contact  deposits  by  J.  F. 
Kemp,  and  as  having  been  developed  by  the  neighboring  gab- 
bro. As  will  appear  fronj  the  accompanying  map  and  section;', 
Figs.  48  and  40,  there  are  two  groups  of  mines.  One  on  Bar- 
ton Hill  is  based  on  a  long  series  of  pods  or  lenses  that  occur 
between  an  underlying  gabbro  and  gabbro-gneiss,  and  an  over- 
lying gneiss,  called  the  (Orchard.  The  Orchard  gneiss  con- 
sists almost  entirely  of  (]uartz  and  oligoclase.  Al)ove  it  is  the 
Barton  gneiss,  containing  some  quartz  with  abundant  micro- 
perthite, plagioclase,  orthoclase,  brown  hornblende,  augite  and 
bypersthene.  The  lower  group  embracing  the  Miller  pit,  Old 
Bed  and  "^1,"  have  the  "21"  gneiss,  an  aggregate  of  (piartz 
and  microperthite,  exposed  on  the  surface.  Diamond  drill  ("(nes 
have,  however,  revealed  the  gabbro-gneiss  beneath  the  ore  iu 
depth.     The  map  brings  out  the  parallel  pod -like  shape  of  the 


J.  F. 


Ill 


irtz 


c(  ires 
bre  iu 
the 


rJ&iflSwiK. 


Fig.  46. — 17('«"  of  open  cut  (tnd  underground  tt'orJc  in  Mine  21,  ^[inei'illc, 
near  Port  Hennj,  N.  Y.     Pliotographcd  hij  J.  F.  Kemp,  1H93. 


"ji" 

Onclsg 


Barron 
Onoiss 

Viu.  4 

iV. 


MAGNETITE  ANP  PYltllE 


163 


Fiti.  4s. — luoliKjicid  map  of  the  iron  mines  at  Mineville,  near  Port  J/enri/, 

iV.  F.    For  dctailn  of  formations  see  text.     After  J.  F.  Kemp,  Trans. 

Amer.  Inst.  Min.  h'ng.,  XXVIL,  146. 


164 


KKMP'8  ORE  DEPOSITS. 


ores.  In  one  instHiice,  the  New  Bed  niines,  the  workings  have 
followed  a  pod  over  2,()()()  ft.  The  magnetites  have  not  yet 
heen  described  in  the  wune  detail  at  other  localities,  but  data 
are  at  hand  which  give  ground  for  similar  inferences  regarding 
several  additional  ones.  Clabbros  are  usually  in  the  vicinity 
of  the  oro  even  when  it  does  not  occur  on  the  contact.  Never- 
theless some  mines  give  no  immediate  evidence  of  the  influence 
of  any  rock  except  that  of  the  walls,  as  for  instance  the  Palmer 
Hill  workings  near  Ausable  Forks;  and  the  ore  appears  to  be 
a  great,   basic  segregation,  drawxi  out  into  a  band,   parallel 


Fig,  49. — Cross-xictidH  of  ore-hmlicti  at  Minctille,  intir  Port  Henry,  N.  T.,  to 

accompany  map,  Fio.  48.     After  J.  F.  h'cvip.  Trans.  Amer. 

Jnxt.  Mill.  Em/.,  XXVIL.  140. 

with  the  foliation.  At  Palmer  Hill  the  walls  are  a  siliceous 
gneiss,  consisting  of  quartz,  microperthite,  microcline  aud 
augite. 

The  ores  follow  all  the  foldings  and  flowing  curves  that  are 
exhibited  in  the  foliation  of  the  gneisses,  and  because  of  tiiis 
they  exhibit  man}'  peculiar  shapes.  They  swell  and  pinch,  roll 
and  fold  and  feather  out.  Still,  at  Mineville  they  show  a 
marked  parallelism  in  the  long  axes  of  the  pods  or  lenses,  and 
M'hile  these  tongue  out  into  the  walls,  they  do  so  with  a  gen- 
eral parallel  aliiiument.  Faults  are  common  and  in  instances 
have  sharply  cut  oft"  the  ore.  Dark,  brecciated  strips  may  mark 


MAGNETITE  AND  PYRITE. 


165 


the  fault  line  and  may  resemble  trap  dikes,  as  in  No.  7  slope  at 
Hammondville.  Small  gulobes  are  frequently  over  the  places 
where  the  ore  is  lost,  and  serve  to  mark  the  fault  line.  Trap 
(likes  are  fre(iuent  in  the  mines,  and  hardly  a  solitary  one  fails 
to  show  them.     They  may  fault  the  ore  for  a  few  feet.' 

3.03.04.  In  their  metallurgical  relations  the  ores  may  be  clas- 
sified, following  the  example  of  B.  W.  Putnam  in  his  report 
for  the  Tenth  Census,  into  (1)  those  high  in  phosphorus,  but 
low  in  sulphur  (Mine  31,  Mineville) ;  (3)  Bessemer  ores,  low  in 
both  phosphorus  and  sulphur  (Barton  Hill  mines,  Hammond- 
ville  mines);   (;5)  pyritous  ores  (BucTj  Mountain,  Ticonderoga). 

'  The  following  papers  relate  especially  to  the  ores  as  distinguished  from 
the  Ki'o'ogy:   L.   (J.   Bec-k,   Mhu'raliHjy  of  New   York,  Part  I.,   1-38,  1843. 
J.  Birkinbine,  " Cr\-stalline  Magiietilo  in  tlie  Port  Henry  (N.  Y.)  Mines," 
Trans.  Amcr.   Inst.  Min.   Eikj.,   XVIII.,   747,    18!)0.     Pet-.     "  Note  on  the 
Magnetic  Separation  of  Iron  Ore  at  tlie  Sanford  Ore-bed,  Jloriah,  Esse.\ 
Co.,  N.   Y.,   1853,   Iileiii,   XXI.,  378,   1893;   see  also  p.  157.     H.  Credner, 
Zi'itsrh.   d.   d.   (J.    (fcsrll.    18(ii»,   XXT.,   p.  51(i;  B.  Hiid   H.   Zeif.,  1871,  369. 
J.  I).  Dana  "On  the  Theories  of  Origin,"  Antcr.  Joitr.  Sci.,  iii.,  XXll.,  153, 
4(12.     E.  Emmons,  Geoluyy  of  New  York,  Second  District,  pp.  87,  98,  331, 
2'>r,.  Sill,  309,  3,50.     Hist.     C.  E.  Hall,  "Laureiitian  IMagiietite  Ore  Depos- 
its of  Northern  New  York,"  ,>Jd  Ann.  Rep.  State  MnscKni,    1884,  j).  133. 
Rcc.     Hanus  Hoefer,  "Die  Kohlen-  und  Eisenerzlagerstiitten  Nord  Amer- 
iiias,"  175,  1878.     J.  F.  Kemp,  "Notes  on   the   ^linerals  Occurring   near 
Port  Henry,  N.  Y.,"  Amcr.  Jonr.  Sci.,  iii.,   XL,  (i3.  inul  Zeitscli.  f.  Kri/st., 
XIX.,  183.     "Tlie  Geology  of  the  Magnetites  near  Port  Henry,   N.  Y.," 
Trims.  Amer.  In,st.  Min.  Emj.,  XXVI.,   14(>,  1897.     G.  W.  Maynard,  "The 
Inm  Ores  of  Lake  Cluun))lain,"  i^/vY.  /)•()((  and  Steel  Inst.,  Vol.   L,   1874. 
F.  L.   Nason,   "Notes   on    Some   Iron-bearing   Pocks  of  the   Adirontlack 
Mountains,"  Avier.  Geoloyist.  XII..  35,  1893.     B.  T.  Putnam  "No<^»s  on  the 
Iron  ]\Iines  of  New  York,"  Tenth  Census.  XV.,  89,  1885.     Rec.     B.  Silliman, 
■  Remarks  on  the  Magnetites  of  Clifton,  St.  Lawrence  County,  N.  Y.*" 
Trans.  Amcr.  fnst.  Min.  Emj.,  I.,  304.     J.  C.  Smock,  "Iron  Mines  of  New 
Yiirk,'  Bntl.  VIT..  N.  Y.  State  MnHcnm.     Pec.    J.   Stewart,    "  Laurentian 
l.ow  (irade  Phosphate  Ores,"  Trans.  Anier.   Inst.   Min.  Kmj.,  XXL,  17(!, 
1S!»3.    Wedding,  Zeitwhr.  f.  B.,  11,  nnd  S.  im.  p.  St.,  Xxfv.,  330,  187(i. 
N(>e  also  the  general  works  on  Iron  Ores  cited  at  l)eginniiig  of  Part  II.     On 
Canailian   magnetites  the   following   pajuM-s   may    be   mentioned:   F.   P. 
I'ewey,  "Some  Canadian  Iron  Ores,"  Tritns.  Anwr.  In.'^t.  Min.  Enff.,XU., 
li'3.    B.  J.  Harrington,  "On  the  Iron  Ores  of  Cajiada,"  Can.  Geol.  Snrre/f, 
1ST3-74.     T.  S.  livmt,  Can.  Geol.  Snrrci/,  18(!(i-(;9,  pj).  2(51,  31)3.     T.  D.  I,ed- 
yard,   "Some  Ontario  ".Uagnetites."  Tran,^.  Amcr.  Inst.  Min.  Eng.,  XIX., 
28,  and  July,  1891.     W.   11.  Jlerritt.  "Occurrence  of  Magnetite  Ore  De- 
posits in  Victoria  County,  Ontario,"  Froc.  Amer.  A,sso.  Adv.  Sci.,  XXXI., 
413,  1883. 


■M.  M 


1 


166 


KEMVti  oiu-:  I > /J /'OS rid. 


On  the  western  side  of  the  mountains  some  extensive  mining 
has  also  been  done.  The  Benson  mines  at  Little  Kiver  are 
based  uj)on  a  broad,  mineralized  zone  whose  ore  is  inclined  to 
be  lean,  and  to  bo  a  subject  for  magnetic  concentration.  There 
are  numerous  deposits  of  magnetite  in  Canada,  to  the  north 
of  Lake  Ontario,  whose  geological  relations  are  similar  to  those 
above  described. 

2.03.00.  Example  V2b.  New  York  and  New  Jersey  High- 
lands, and  the  South  Mountain  of  Pennsylvania.  Lenticular  or 
pod-like  masses  of  magnetite  in  Arcbeau  gneiss  and  crystalline 


Fui.  r>().  Fig.  51. 

Figs.  50  and  51. — yfodil  of  the  Tilly  Foster  ore  body.    50.  Sid:  view,  alioio- 

ing  f united  shoulder.     After  F.  S.  liuttmann.  Trans.  Amer.  Inst. 

Mill.  KtKj..  A'F. ,  70.     51.  View  of  bottom  of  same.  Photo- 

f/raphed  hy  J.  F.  Kemp  from  the  mudel  now  at  the 

School  of  Mines,  Columbia  College. 

limestone.  From  Putnam  County,  New  York,  a  ridge  of 
Archean  rocks  runs  southwest  across  the  Hudson  River,  trav- 
ersing Orange  County,  New  York,  and  northern  New  Jersey, 
and  running  out  in  Pennsylvania.  Lenses  of  magnetite  occur 
tlirougbout  its  entire  extent.  They  are  not  as  large  as  some 
in  the  Adirondacks,  but  they  are  more  regularly  distributed. 
East  of  the  Hudson,  in  Putnam  County,  the  Tilly  Foster 
mine    is     the    most    important,    and    the     descriptions    and 


MAGNKTfTi:  .!  V/>   rvniTK. 


Ifi? 


tij^ures  of  it  are  the  best  illiiHtratioiia  of  the  shape  of  louses 
|)iil)lisheil.  West  of  the,  Hudson,  in  Oranj^e  County,  tlio 
Forest  of  Dean  mine  att'onls  considerable  ore  yearly.  It  is 
cut  by  an  interesting  trap  dike.  As  the  results  of  study 
of  the  Archeau  of  this  region,  N.  L.  Britton  has  diviiled 
it  into  a  Lower  Massive  grouj),  a  Middle  Iron  Bearing, 
and  an  Upper  Schistose,  {(ieol.  of  N.  ./.,  1880,  p.  7  7.) 
F.  L.  Nason  has  also  sought  to  classify  it  on  the  k^'-is  of  rock 
types,  of  which  he  makes  four,  named,  from  their  typical  occur- 
ipuces,  Mount  Hojje  type,  Oxford  type,  Franklin  ty{)e,  and 
Moutville  type.  They  are  arranged  in  their  order  of  probable 
Hge.  They  correspond  in  some  respects  to  Britten's  grouping, 
l)ut  differ  materially  in  others,  {(ieol.  of  X.  ./.,  18S1),  p.  ;}().) 
Four  courses,  or  mine-belts,  bave  been  recognized  in  New  Jer- 
sey—the Ramapo,  the  Passaic,  the  Musconetcong,  and  the 
Peciuest — in  order  from  east  to  west.  The  lenses  strike  north- 
east with  the  gneisses,  and  usually  have,  like  them,  high  di})s. 
lu  addition  they  have  also  a  so-called  "pitch"  along  the  strike, 
so  that  they  run  diagonally  down  the  dip.  They  have  been 
observed  to  pitch  northeast  with  an  easterly  dip  and  southwest 
willi  a  westerly.  Either  hy  the  overlapping  of  lenses  or  by  an 
approxiiuation  to  an  elongated  bed,  they  sometimes,  as  at 
Hi  hernia,  extend  a  mile  or  more  in  unbroken  series.  Again, 
they  may  be  almost  circular  in  cross  section  (Hurd  mine).  At 
Franklin  Furnace  one  is  found  in  crystalline  limestone.' 

'  E.  S.  Breidenbaugh,  "On  the  Minerals  Found  at  the  Tilly  Foster  Miue, 
New  York,"  Amer.  Jour  Sci.,  iii.,  VI.,  207.  J.  F.  Kemp,  "  !  >iorite  Dike  at 
the  Forest  of  Dean  Mine,"  Idem,  iii.,  XXXV.,  a;51.  F.  Ji.  McDowell, 
"The  Reopening  of  the  Tilly  Foster  Mine,"  Trans.  Anier.  Imt.  Miu. 
Kny.  XVJl.,  ToH;  Eughieeritnj  and  Mining  Journal,  Sept.  7,  18S!), 
I'li'i.  F.  8.  Ruttnian,  "  Notes  on  the  Geology  of  the  Tilly  Foster  Ore 
MiHly.  Putnam  County,  New  York,"  Trans.  Amer.  Innt.  Min.  Eng.,  XV., 
Til  Ueo.  J.C.^movk,  Bull  VII.,N.Y.  State  Museum.  Rec.  A.  F.  Weudt. 
•  Tlie  Iron  Mines  of  Putnam  Countj',"  Trans.  Amer.  Iihtf.  Min.  Eng., 
Xiil.,  ITS.  "Iron  Mines  of  New  Jersey,"  »SW( oo/  of  Mines  Qnarterli/,  iv., 
111.  N.  L.  Britton,  Ana.  Rep.  N.  J.  Sm-veij,  1886,  p.  77.  Ree.  G.  H. 
Cook  and  J.  C.  Smoek,  Geol.  of  N.  J.,  1808.  Rec.  (See  also  sul)se(inent 
aiunial  reports,  esi)ecially  1873,  p.  13.)  F.  L.  Nason,  Ann.  Hep.  K  J. 
•'Surrcij.  1889.  Rec.  J.  W.  PuUmann,  "  The  Production  of  the  Hibernia 
Mme.  N,.w  Jersey."  Trans.  Amer.  Inst.  Min.  Eng.,  XIV.,  5)04.  J.  C. 
Siiidck, 'The  Magnetite  Iron  Ores  of  New  Jersey,"  Idem.  II.,  814;  "A 
Review  of  the  Iron  Mining  Industry  of  New  Jersey,"  Idem,,  June,  1891. 
Rec. 


1  1! 


1G8 


A'A'J//'s  nliH  Ohl'OSrrS. 


J.  E.  WulfT  haw  C()iitril)ute(l  a  very  important  and  HUggcHtive 
paper  upon  the  large  IkhI  of  magnetite  at  Hibernia.  The  ore 
extends  for  about  one  mile  aH  developed,  and  fonuH  a  persist- 
ent  band  in  a  sericH  of  gnei.sHes  wJiich  under  the  niieroHeope  are 
found  to  contain  (piart/,  ortlioebiHe,  plagicxdase,  micnx-jiiie, 
microportbite,  brown  or  green  borubleudo,  a  deep  green  or  color- 


i--:,--. 


.^^^ 


Fia.  52. — Sketch  map  iUustratiiif/  the  geological  stt'ucturfi  of  the  Ilibernia  mag- 
netite bed,  J  fiber  )iia,  N.  J.     The  ore  outcrops  for  one  7nile.     Ajter  J.  K. 
Wolff,  Annual  Report  of  the  State  Geologist  of  New  Jersey  for  189;>. 

less  augite,  sometimes  diallage,  biotite,  sometimes  byperstbene. 
and  as  accessories,  apatite,  magnetite,  and  zircon.  The  dark 
silicates  may  form  intermittent  bauds  bj'  tbeir  greater  abund- 
ance, but  are  of  no  stratigrapbic  value.  All  the  large  minerals 
are  in  elongated  spindles,  whose  long  axes  correspond  to  tlie 
pitch  of  the  gneiss.     They  are  thought  by  Wolff  to  have  as- 


MA(}NF/riTI':  AND   PYlilTK. 


100 


sumed  this  Hliape  in  orystalliziii^,  during  metaniorpliism.  About 
ii  half  mile  from  the  ore  and  parallel  with  it  ia  a  band  of 
liiotito-garnet-grapliite  gueiss  that  is  perniHtent,  and  that  is 
folded  as  shown  in  Fig.  ^)'l.  This  latter  rock  is  supposed  to 
lie  a  inetaniorphosod  limestone,  and  the  whole  series  is  regarded 
as  metamorphosed  sediments  by  Wolff.'  F.  L.  Nason  has 
worked  out  the  structural  geology  of  the  Ringwood  mines,  and 
has  found  that  they  are  <|uite  well  interpreted  as  lying  along  a 
pitching  series  of  folded  gneisses."' 

:i. (»;').()(;.  South  Mountain,  Pa.  Small  lenses  of  magnetite 
occur  in  Berks,  Bucks,  and  Lehigh  Counties  of  southeastern 
Pfinisylvania,  in  the  metamorphic  rocks  of  the  South  Moun- 
tain belt.  They  are  very  like  those  to  the  north  in  New  Jer- 
Hey,  but  are  lower  in  both  iron  and  })hospborus.  Their  product 
liHs  reached  1  ()(),( KM)  tons  j'early.  The  Cornwall  magr.dtite  is 
described  under  Example  l^i,  for  its  geological  stuicture  is 
entirely  different  from  the  lenses."' 

•^M);5.()('.  Example  V2c.  Western  North  Carolina  and  Vir- 
ginia. Beds  of  nuignetite,  of  the  characters  already  described, 
in  Archean  gneisses  and  schists.  The  ore  body  at  Cranberry, 
N.  C,  is  the  largest  and  best  known.  It  occurs  in  Mitchell 
County,  and  has  lately  been  connected  by  rail  with  the  lines  in 
east  Tennessee.  According  to  Kerr,  the  principal  outcrop  is 
1,500  feet  long  and  'ZW  to  800  feet  broad ;  but,  of  course,  this  is 
not  all  ore.  The  mines  can  afford  very  large  (juantities  of  excel- 
lent Bessemer  grade.  P^'roxene  and  epidote  are  associated  with 
the  ore.  Kerr  has  referred  the  magnetite  to  the  Upper  Lauren- 
tiiin.  In  the  southern  central  portions  of  North  Carolina  other 
niaj^'uetites  occur  in  the  mica  and  talcose  schists,  which  have 
been  referred  to  the  Huronian.  (See  H.  B.  C.  Nitze,  Bull. 
I..  N.  C.  Geol.  SVrfe//,  for  detailed  report. )  (Example  10.) 
Magnetite  has  also  been    lately  reported  from  Franklin  and 


'  .T.  K.  Wolff,  "(ieoloftit-al  Htructin-e  in  tlie  Vicinity  of  Hibernia,  N.  J., 
aiil  its  iJelation  to  the  Ore  Deposits,"  .V.  J.  Geol.  Siiririj.  Isi);^.  :',r,\). 

'  F.  L.  Nason,  "  The  Geoloj^ical  Structure  of  the  Ringwood  Iron  Mines. 
N.  J.,"  Tram.  Amvr.  Lint.  Min.  Eikj.,  XXIV..  50.-),  1S!»4. 

n<:.  V.  d'lnvilliers.  Rep.  D;},  Pciiu.  Survt'i/,  Vol.  II.  (Soutli  Mountain  Belt 
of  Berks  County).  Rec.  F.  Prime.  Rep.  D:5,  Vol.  I.,  Peun.  Survey  (Lehigh 
County).     B.  T.  Putnam,   renth  Census,  Vol.  XV.,  p.  179. 


lit 


no 


KH.MI'S  (HIK  /ih'/'OsnS. 


Henry  Counties,  Virj^inia,  and  StokeH  County,  North  Carolina. 
Some  doubt,  however,  in  caHt  on  its  amount  and  <iuality.' 

'^'.(>;j.Os.  Example  I'id.  Colorado  Maj,'netit' is  Hedn  of 
maf^nctito  of  u  lenticular  cluiractor  in  rocks  dcscrihed  as  sye- 
nite (ChatYeo  County)  and  diorite  (Fremont  County).  With 
these  a  number  of  others  are  mentioned  which  vary  from  the 
example,  Imt  of  which  more  information  is  needed  before  they 
can  be  well  classified.  The  last  are  mere  prospects.  The  mines 
in  Chaffee  County  have  been  tiie  only  actual  producers.  There 
are  three  principal  claims — the  Cahunet,  Hecla  and  Smithtield. 
They  extend  continuously  over  4, ()(»()  feet.  The  wall  rock  is 
called  syenite.  Chauvenet  describes  them  as  having  resulted 
from  the  oxidation  of  pyrites,  and  as  being  in  rocks  of  Silurian 
age.  They  average  ru%  Fe,  with  only  0.()l)!»  P,  but  are 
comjiaratively  high  in  S,  reaching  o.  1  to  '-.'.(("o.  These 
mines  and  those  at  the  Hot  Springs,  mentioned  under  Ex- 
ample 'i,  have  fm-nished  the  Fuebhj  furnaces  with  most  of 
their  stock.  The  deposit  in  Fremont  Coimty  is  at  Iron  Moun- 
tain, but  is  too  titaniferous  to  be  valuable.  It  is  a  lenticular 
mass  in  olivine-gabbro,  and  is  again  referred  to  under  2.U'.i.  11. 
A  large  ore  body  has  been  ro])orted  from  Costillo  County,  in 
limestone  (Census  Keport)  or  sj'enite  (Kolker).  In  Gunnison 
County,  at  the  Iron  King  and  Cumberland  mines,  excellent 
ore  occurs  in  (juartzitos  and  limestones,  called  Silurian.  At 
Ashcroft,  near  Aspen,  high  up  in  the  northern  side  of  the  Elk 
Mountains,  is  a  great  bed  or  vein  of  magnetite  in  limestones 
of  Carboniferous  age  with  abundant  eruptive  rocks  near.  It 
is  thought  by  Devereux  to  be  altered  pyrite.  Still,  pyrite  is  a 
common  thing  with  magnetite  elsewhere.  There  are  otlier 
smaller  deposits  in  Bowlder  County,  and  elsewhere  in  the  State." 

'  H.  S.  Cliase,  "Southern  JhiKnetites  and  Magnetic  Heifamtion,"  Trans. 
Amcr.  JuHf.  Miii.  Eiiij..  X\\  .J^rA-T)')!,  ISltti.  W.  V.  Korr,  dciloyn  of  Xorlli 
Carolina,  1875,  2(54.  J.  P.  Kiniball,  "On  theilagiiHtite  Helt  atCninWern, 
N.  C,"  etc.,  Amer.  Geo!.,  XX.,  2!t»-;n3,  1807.  H.  B.  C.  Nitze,  "  Notes  on 
the  Magnetites  of  Soutinvestern  Virginia  and  tlie  Contiguous  Territory  of 
Nortli  Carolina,'  Tnaix.  Anicr.  Inst.  Min.  Emj.,  XX.,  174,  and  discussion, 
185.  -Tiie  Miignetic  Iron  Ores  of  Ashe  Co.,  N.  C,  Idem,  XXI., 'JCII. 
"  Magnetic  Iron  Ore  in  (Jranville  Co.,  N.  C,"  Eng.  and  Min.  Jour.,  April 
2;$,  18i)2,  J).  447.  B.  Willis,  Tenth  Ccnxm,  XV.,  825;  Enrj.  and  Min.  Jour., 
Jan.  7,  1888.     Kerr  and  Haiina,  "  Ores  of  North  Carolina,"  18!(;{. 

'  E.  Chauvenet,  "Papers  on  Iron  Prospects  of  Colorado,"  .i4/t».  A'c/w. 
Colo.  State  School  of  Mines,  1885  and   1887;  also  Trann.  Anier.  In.sl.  Miit. 


MAGNETITK  ANh   rVlilTK 


171 


2.03.09.  In  Wyoniiu{^an  iinnuiiisti  inuHH  of  titaniforouH  iimg- 
iiotite  is  known  near  Cliiigwater  Creek.  It  is  more  fully 
(Icscriliod  under  Kxaniplo  l.'{,  with  which  typo  of  ore  body  it 
boloiigH. 

•^.();{.  10.  Example  rjc.  California  Maf^netito.  KedHofniag- 
uetite  of  lentirular  wliapo  in  metamorphic  slaten  and  limeHtones 
on  the  western  wlopo  of  the  Sierra  Nevada.  ( )th('rH  of  dilVercnt 
rliiiraoter  are  also  known.  In  Sierra  and  Placer  counticw  lenses 
of  (xcudlent  ore  aro  found,  accompanying  an  extended  stratum 
of  linieHtono  in  chlorite  slate.  A  groat  ore  body  of  magnetite 
described  as  a  vein  has  lately  been  rept)rted  from  San  Hernard- 
ino  County.  It  is  said  to  he  from  ;{(»  to  l.">0  feet  thick,  and  to 
lie  between  dolomitic  limestone  and  syenite.'  A  groat  bed  of 
a  kind  not  s])ecitied  is  reported  from  San  Diogo  County." 

•,*.(i;i.  11.  Example  IM.  Masses  of  titaniforous  magnetite  in 
i^'ueous  rocks  which  are  most  often  gahbros  or  relatod  typos, 
(ioneral  commonta  were  made  upon  these  in  l.Ofl.  11  and  l.dil.  Ki. 
In  many  cases  such  ore  bodies  seem  undoubtedly  to  he  exces- 
sively basic  segregations  of  fused  and  cooling  magmas.  Whether 
tliB  toiulency  of  these  early  crystallizations  to  concentrate  is  duo 
to  Sorot's  principle,  to  magnetic  curnints  or  attractions,  or  to 
the  liigh  specitic  gravity  of  the  mineral  which  might  cause  it 
to  sink  in  the  magma,  is  perhaps  not  alwa^'s  clear,  for  all  these 
explanations  have  been  suggested.  The  masses  are  not  yet  of 
practical  value  in  North  America,  and  hence  are  not,  strictly 
speaking,  ores;  hut  no  one  familiar  with  their  size  and  amount 
can  resist  the  conviction  that  they  will  ultimately  be  utilized. 
The  commonest  rocks  forming  the  walls  are  gabbros,  noritos, 
thorites  or  peridotites,  all  of  which  are  close  relatives.  Later 
nietaniorphism,  such   as   mountain-making    processes  and  the 

A''i(/.,  Denver  meeting,  1889.  Reo.  W.  B.  Devereux,  "Notes on  Iron 
l'ii»l>pcts  in  Pitkin  County,  Colonul"!.'  Tniiis.  Aiiin:  Insf.  Min.  Km/., 
Xll,  (Kis.  B.  T.  J'utniun,  7(/(//i  (>y/.s/«.s,  Vol.  XV.,  p.  4T3.  Keo.  CM. 
Itolker,  "Notes  on  Iron  Ore  Depo.sits  in  Colorado,"  Tniiix.  Amer.  Inst. 
Min.  Eng.,  XIV..  '2()(».     Keo. 

'  Ann.  Hep.  State  Miueritlo(jint,  ISSi).  ji.  -i'i'h 

'  Ihi'l.  1SH9,  p.  l,-)4.  J.  R.  Browne,  '•  Mineral  Resounres  West  of  the 
Kocky  Mountains,"  18()8.  C.  King  and  J.  D.  Hague.  "Mineral  Re.sources 
West  oltlie  Rocky  Mountains."  IHM,  p.  44.  H.  (}.  Hanks  ami  W.  Irelan. 
Ann.  Hij).^.  State  Minentlojist.  California.  (Very  little  on  iron. )  F.  von 
Hiclitliot'cn,  private  reports  quoted  in  Tenth  Cciiaus,  Vol.  XV.,  p.  4it."). 
J.  1)   Whitney,  G-ol.  S'lrv.-i/  of  Cal,  Vol.  I. 


■M 


17-;? 


KEMPS  ORE  DEPOSITS. 


like,  sometimes  give  the  wall  rock  a  gneissic  structure  and 
stretch  out  the  ore  into  apparent  beds.  The  ores  have  some 
cliaracteristic  peculiarities  of  chemical  and  niineralogical  com- 
position. As  a  rule,  although  not  invariably,  they  are  low  in 
sulphur  and  phosphorus.  On  analysis  they  almost  always 
afford  small  percentages  of  vanadium,  chromium,  nickei  and 
cobalt.  They  may  be  so  rich  in  alumina  and  magnesia  as  to 
indicate  the  presence  of  spinel.  In  fact,  one  variety  of  these 
ores,  that  is  found  near  Peekskill,  N.  Y.,  and  at  Routivara,  in 
Swedou,  is  an  aggregate  of  spinel  and  titaniferous  magnetite. 
Ores  of  this  variety  show  genetic  relations  with  some  deposits 
of  emery  and  corundum.  The  pig  iron  afforded  I)}'  tiio  titanif- 
erous ores  has  certain  excellencies  peculiar  to  itself  that  may 
be  due  to  one  or  more  of  the  above  ingredients.' 

Many  years  ago  T.  S.  Hunt  recognized  the  fact  that  the 
titaniferous  ores  of  Canada  and  the  Adirondacks  were  limited 
to  the  labradorite  rocks  of  the  Norian  or  Upper  Laurentian 
series.  It  is  now  known  that  they  may  occur  both  in  auor- 
tliosites  and  in  basic  gabbros.  The  ore-bodies  are  of  enormous 
size  on  the  lower  St.  Lawrence  (Bay  St.  Paul),  on  the  Sagiie- 
nay  River,  and  near  Lake  Saudford,  in  the  heart  of  the  Adiron- 
dacks. Smaller,  but  still  very  large  masses,  are  known  in  Que- 
bec, nortli  of  Montreal;  in  Ontario,  north  of  Kingston  ;  in  West- 
port  and  Elizabethtowu,  N.  Y.,  and  in  several  other  places  not 
far  from  the  national  boundarj'.^ 

'  Tlie  chemical  characters  are  discussed  by  J.  F.  Kenap  in  a  paper  on 
"The  Ti tail ifer HIS  Iron  Ores  of  the  Adirondacks,"  Nineteenth  Atoi.  Rrp. 
Dir.  U.  S.  (h'oJ.  Siirrc!/.  Part  III.,  p.  ;577.  A  (h'tailf»d  review  of  titanifcr 
oils  ores  tlie  worhl  over,  by  tlie  same  writer,  will  be  found  in  the  ScIkkiI 
of  3liiieii  QiKirtcrlij,  July  and  November,  1899.  All  the  analyses  known 
to  l)e  piibhshed  to  date  are  compiled. 

"  On  the  Canadian  ores  see:  F.   D.   Adams,    "  Ueber  tftis   Norian  oder 
Ober-Laurentian  von  Canada,  Neiies  Jnhrhuch,  Beihige  Band.  VIII..  410; 
:in  Knj^lish   translation  will  be  fou.id  in  the  CaiiadifDi  Rrconl  of  Sciiiwe. 
1894.  l()9;   189."),  Jan.,  p.  1,  July,  p.  1.     "On  the  I<j;neous  Origin  of  Certain 
Ores,"  Proe.  General  Mining  AnHociation  of  the  Province  of  Qnehee,  ,lan. 
12,   1894.     E.J.  Chapman,    "On   Some  Iron  Ores   of  Central   Ontario," 
7VnH.s.  Royal  Soe.  of  Can..  188r),  9.     See  also  7r/f-/«,  1884,  159.     R.  W.  Ells, 
Geol.  Snrreii  of  Canada.  1888-89,  14K.     B.  J.  IIarrinf,'ton,  Idem.  18r:!-T4. 
2'?7.     T.  S.  Hunt.   Idem,  1847,  09;  1807,  213.      F.  J.   Pojie,  "  Titanifenms 
Ores  of  Ontario,"  Tra  i.'i.  Amer.  In.'^t.  Min.  Eng.,  :\Iay,  1899.     On  the  oiw 
in  New  Ycn-k  see:  E.  Emmons'  Rei)ort  on  the  Second  Di.strict,  N.  Y..  Stiite 
Survey,  244.  1843.     J.  F.  Kemp,  "The  Titaniferous  Iron  Ores  of  the  Adi- 


MAGNETITE  AND  PYRITE. 


173 


The  ores  near  Peekakillare  low  iu  titanic  oxide,  not  ranging 
above  four  per  cent.,  but  they  are  extremely  rich  in  alumina, 
and  attention  was  first  directed  to  them  by  J.  P.  Kimball,  on 
account  of  this  ingredient.  They  constitute  excessively  basic 
developments  in  the  norites  of  the  Cortlandt  series  of  gabbroic 
rucks,  that  cover  about  twenty-five  square  miles  on  the  Hudson 
River,  They  ai*e  also  present  as  small,  separate  dikes.  They 
consist  of  spinel,  magnetite,  corundum,  garnet  and  occasional 
siilimanite,  and  are  remarkably  close  parallels  with  some  results 
of  artificial  experiments  obtained  by  Josef  Morozewicz.  They 
Lave  been  utilized  for  emery  and  are  near  relatives  in  a  geo- 
logical way  to  s(mie  deposits  of  corundum  and  emerj'.' 

A  very  curious  and  interesting  knob,  or  boss,  of  peridotite  is 
exposed  at  Iron  Mine  Hill,  Cumberland,  R.  I.,  that  is  so  en- 
riched with  titaniferous  magnetite  as  to  receive  attention  as  an 
ore.  It  protrudes  through  mica  schists  and  is  closely  akin  to 
the  Swedish  one  at  Taberg,  as  was  recognized  many  years  ago 
by  ]\1.  E.  Wadsworth.'^ 

A  belt  of  titaniferous  ores  traverses  New  Jersey  and  affords 
magnetites  of  moderate   percentages  of  Ti(  )2. '      Several  belts 

loiulucks,"  Nineteenth  Ann.  Rep.  Director  U.  S.  Oeol.  Survey,  'Yi7,  ISfl!). 
Also  Fiffrenth  Ann.  Report  of  N.  Y.  State  Geologist,  fiOH,  ISOS.  (I. 
W.  Jlayiiard,  " The  Iron  Oros  of  I.ako  Cliaini)ljiin,"  Jo^u'.  lirif.  Iron  and 
Sti  l  lust..  I.ST4.  A.  J.  Rossi,  "Titaniferous  Ores  in  tlie  Blast  Furnace," 
Tmns.  Aincr.  Inst.  Min.  Eng..  XXL,  882,  1893.  "  The  Smelting  of  Titan 
ilVrous  Ores,"  The  Iron  Age,  Feb.  C.  and  20.  ISiKi. 

'  J.  D.  Dana.  Anier.  Jour.  Sei.  Further  notes  l)y  (i.  H.  Williams,  /(/(/((, 
Feb..  1887,  1!»4.  J.  P.  Kimball,  Anier.  CliemiHt,'  IV.,  18T4,  331  ;  Trans. 
Aiiirr.  fn.'it.  Min.  En;/.,  IX.-,  li>,  1880.  Their  geologieal  relations  will  be 
more  fully  described  in  a  forthcoming  paper  by  J.  F.  Kemp  and  M.  B. 
Yung.  Ou  tlie  artificial  production  of  these  ore  mixtures,  see  Josef 
M(ini/.e\vicz.  T.-<clierni((lt-s  Min.  a.  Petr.  Miftli.,  "On  the  Reluted  Swedish 
Ores.  •  VV.  Petterson,  (U'ol.  Eiiren.  inSf<.;'h:holni  Forluindl.,  XV.,  45,  1893. 
H.i-  Sjogren,  Jdcni.  .')."»  and  140. 

'  M.  E.  Wadsworth,  "  Lithological  Studies,"  Bnlt.  Mi(s.  Camp.  ZHol. 
Harvaril  College,  VIT.,  18S|,  18;?.  A  later  note  will  be  found  in  t\m Biillrtin 
Aiiirr.  Iron  and  Steel  Assoeiation,  Nov.  20,  ls,s!».  See  also.  A.  T-.  llolley, 
Tnitis.  Amer.  ///.s/.  Min.  Eng.,VI.,  224,  18T7.  C.  T.  Jackson,  Giologieal 
Snrrcn  of  Rhode  Islamt.  53,  1840.  N.  S.  Shaler,  Sixfeentli  Ann.  Rep. 
V.  S.  Cliitl  Snrrei/,  II.,  321.  Bull.  Mas.  Voinp.  Ziioi.,  Harvard  College, 
XVI.,  1S.5.    B.WUlis,  Tenth  Census,  XV..  mi. 

On  New  Jersey,  .see  the  Annual  Reports  of  the  State  Geologist  as 
follows;  1873,  53,  55:  1875,  35;  187«,  54;  1877,  49;  1878,  W),  100;  187!),  ()2, 
<(T.  7(;;  \HH{),  125.     R.  W.  Raynum.l,  Trans.  Amer.  Inst.  Miii.  Eny.,  XXL, 


174 


KEMP'S  ORE  DEPOSITS. 


occur  in  North  Carolina.'  The  wall  rocks  have  not  been  as 
yet  accurately  determined  in  either  State.  In  the  extreme 
northeastern  corner  of  Miimesota,  on  Mayhew  Lake;  and  at  other 
points  within  the  huge  area  of  gabbros  in  this  State,  the  ores 
are  known,  and  some  small  amount  of  work  has  been  expended 
on  them.^  Titaniferous  ore  has  been  described  by  Arnold 
Hague  as  forming  great  dikes  in  granite  on  Chugwater  Creek, 
Wyo.  Olivine-gabbro  and  anorthosite  are  in  the  neighbor- 
hood, and  have  been  determined  as  the  wail  rock  of  at  least  one 
mass  of  ore  by  B.  F.  Hill.''  The  rock  was  collected  by  W.  G. 
Knight.  The  ores  are  also  known  in  at  least  three  places  in 
Colorado.  One  is  in  Fremont  County,  at  the  so-called  Iron 
Mountain,  which  is  situated  about  fifty  miles  west  of  Pueblo, 
in  the  Wet  Mountain  valley,  on  a  tributary  of  Grape  Creek. 
A  sample  of  rock  believed  to  have  come  from  the  walls  has 
been  determined  by  J.  F.  Kemp  to  be  an  olivine-gabbro.*  An- 
other locality  is  Caribou  Hill  in  Boulder  County.''  and  a  third 


1893,  STH.  B.  F.  Faokenthai,  Mem,  279.  Isidor  Walz,  Amer.  Chemist, 
June,  18T0,  453.  The  Cliurch  iniue  on  Sehooley's  Mountain  is  the  best 
known  one. 

'  On  North  Carolina,  see  North  Carolina  Geol.  Survey,  II.,  1893,  181. 
J.  P.  Le.sley,  "  Notes  on  tlie  Titaniferous  Iron-ore  Belt  near  Greensboro, 
N.  C,"  Proc.  Amer.  Phil  Soe.,  XII.,  1871,  139.  H.  B.  C.  Nitze,  BiiIHin 
I.,  X.  C.Geol.  SuriH'y.  Bailey  Willis,  "On  the  Dannemora  Mine,"  Tetdh 
Census,  XV.,  310. 

"  W.  S.  Bayley,  "Peripheral  Phases  of  the  Great  Gabbro  Mass  of  Nortli 
eastern  Minnesota,"  Joiir.  Qeol.,  Vol.  I.,  p.  818.  See  also,  for  notes  on 
their  i)etrofrrapiiy.  Idem,  Vol.  III.,  p.  1.  C.  R.  Van  Hi.se,  Bull.  Geol.  Soe. 
Amer.,  VII.,  1895,488.  N.  H.  Winohell,  Tenth  Ann..  Rep.  Minn.  Geol. 
Survey.  1882.  85.     N.  H.  and  H.  V.  Winchell,  Bulletin  VL.  Mem,  13(i.    U. 

E.  Wadsworth,  Bulletin  11 .  Idem,  fi3,  73. 

^  Arnold   IhiKue,    U.  S.   Geol.  E.rplnr.  Fortieth  Parallel,  II.,  12,  1877. 

F.  V.  Harden,  U.  S.  Geol.  and  Geogr.  Survey,  Territories  1870,  14.  B.  F. 
Hill,  Sehool  of  Mines  Quarterly.  July,  1899.  W,  G.  Knight,  Bull.  XIV. 
Wyo.  Agric.  E.vperinient  Station,  177,  1893.  Howard  Stansbury,  E.v- 
ploration  and  Survey  of  the  Valley  of  the  Great  Salt  Lake,  1853,  266.  F. 
Zirkel,  U.  S.  Geol.  Rrplor.  Fortieth  Parallel,  VI.,  107. 

*  F.  M.  Endlich,  U  S.  Geol.  and  Geogr.  Surivy  of  the  Territories,  18T3, 
333.     B.  T.  Putnam.  Tenth  Census,  XV.,  473. 

'  Regis  Chauvenet,  "Notes  on  Iron  Prosjiects  in  Northern  Coloradd," 
Biennial  Rept.  of  the  Colo.  State  School  of  Mines,  1886,  16.  B.  T.  Ptitiiiiiu. 
Tenth  Censtis,  XV.,  416. 


MAGNETITE  AND  PYRITE. 


176 


is  in  the  Cebolla  district,  GuDnison  County/  where  the  amount 
is  reported  to  be  large.  The  orea  in  basic  nepheline  rocks  in 
Brazil'^  are  the  only  others  in  the  Western  Hemisphere.  The 
Swedish  and  Norwegian  ores  are  similar  in  their  geological  rela- 
tions to  tlie  several  American  types,  viz. :  those  at  Ekersund 
and  SoggendahljMo  the  ores  of  Quebec  and  the  Adirondacks; 
those  at  Routivara^  to  the  aluminous  ores  of  the  Cortlandt 
series;  the  Taberg"  ore  is  like  that  at  Cumberland,  R.  I. ;  and 
the  Alno"  occurrence  resembles  the  Brazilian  type.  The  titan- 
iferous  iron  sands  will  he  referred  to  under  magnetite  sands. 

2.03. 1"^.  Example  U.  Cornwall,  Pa.  Deposits  of  soft 
magnetite,  resting  against  igneous  dikes  and  associated  with 
green,  pyritous  shales,  Siluro-Cambrian  limestone  and  Trias- 
sic  sandstone.  These  ore  bodies  are  to  be  classed  among  the 
largest  ever  mined.  They  form  three  hills  extending  in  an  east 
and  west  direction,  and  called  respectively  Big  Hill,  Middle 
Hill  and  Grassy  Hill.  As  the  accompanying  contour  map 
shows.  Big  Hill  is  the  highest  and  narrowest,  while  Middle 
Hill  contains  the  most  ore.  The  hills  lie  just  at  the  southeast- 
ern edge  of  the  Great  Valley,  and  are  six  miles  from  the  flour- 

'  Regis  Chauvenet,  "Iron  Resovirces  of  Gunnison  Co.,"  ^  »(<'/•.  Rep.  Col. 
State  Seliool  of  Mines,  IHST,  18.  "Iron  Resources  of  Colorado,"  Trans. 
Amer.  Inxt.  Min  Eng.,  XVIII.,  372.  Arthur  Lakes,  "The  Great  Cebolla 
River  Deposits,"  Colliery  Engineer,  XVI.,  3(57,  1896. 

I  0.  A.  D(Mby,  ' '  Magnetite  Ore  Districts  of  Jacupiranga  and  Ipanema, 
Sao  Paulo,  Brazil,"  Anier.  Jour.  Sci.,  April,  1S91,  ;U1. 

'  T.  Dalil,  FOrhandl.  videnskub.H  JVatm.  i.  Stockholm,  1863.  D.  Foi-bes, 
Chem.  AV?'',s,  December  11,  1868,  275.  S.  Forbes,  Jour.  Brit.  Iron  and 
Steel  Innt.,  1874,  i:51.  Th.  Kjerulf.  A7yf.  Magazinfor  Aatv.,  XXXIL,  \Hm. 
H.  Rose.nbusch,  Idem.  T.  C.  Thomassen,  Idem,  XXIV.,  287.  C.  F.  Kol- 
il'Tup.  Bergen  H  Mu.Heuui'n  Aarbog.  in  Sforliliolm.  18!)(i.  l."i!).  Rec.  IT.  H. 
Kcusch,  Geol.  Foren  in  Sfockliolm.  1877.  lt»7;  Neiie.'^J(ihrl)iieh.  1878.  J.  H. 
L.  Vugt,  Idem,  XIII.,  476,  08:5,  XIV.,  311;  Geological  Magazine,  IX.,  82; 
XeurnJahrlmch,  \Hm,  II.,  m,  Zeitnehr.  fur  prakt.  ^co/ofiffV,  January.  18i>:i, 
6;  OctolxM",  18!M,  ;?84;  Areliir.  fi'ir Mathem.  og  Xatnrriden.^kab,  Kristiania, 
X.  1111(1  XII.,  1887.  The  i>a|)ers  of  Kolderup  and  Vogt  are  of  chief  value 
for  rc^ference. 

'  W.  IVtterson,  Geol.  Foren.  i.  Stockholm.  XV.,  45.  1893;  (Nenes  Jahr- 
hiich.  1H!(4,  I.,  88);  H.  Hjogren,  Idem,  XV.,  55,  140,  1893;  (Neiies  Jahrbuch, 
l«i»4,  L,  88). 

'  A.  Sjogren,  Geol.  Foren.  i.  Stockholm,  III.,  42,  1876;  (Xenes  Jahrbuch, 
lH7(i,  4:M).  a.  E.  Torncbohni,  Idem,  V..  610;  Neuen  Jahrbuch.  1882,  II.,  66. 
J    H.  L.  Vogt,  Zeitschrift  fi'ir  prakt.   Geologic,  January,  1893,  8. 

'  A.  G.  lloegboni,  Geol.  Foren.  i.  Stockholm,  XVII..  "lOO,  214,  1895. 


ail 


'176 


KEMP'S  ORE  DEPOSITS. 


ishing  little  city  of  Lebanon.  The  geological  section  (Fig.  .5,3) 
illustrates  the  position  of  the  strata.  The  Siluro-Canibrian 
series  its  '^"t  by  an  immense  diabase  dike  near  its  southeastern 
limit,  and  on  the  south  side  of  the  dike  which  forms  the  north- 
ern rampart  of  the  three  hills  lies  the  ore.  The  ore  is  a  soft, 
rather  earthy  magnetite,  which  occasionally  shows  octahedra. 
While  richer  and  purer  on  the  original  weathered  surface,  it  is 
now  interlaminated  and  closely  involved  with  layers  of  limey 
shales  vvhicli  contain  pyrite,  at  times  in  beautiful  crystals. 
Most  of  the  ore  is  merchantable  raw,  but  large  quantities  are 
so  low  from  tliis  admixture  of  shales  that  they  are  being  saved 
for  possible  future  magnetic  concentration.  The  presence  of 
the  pyrite  makes  it   necessary  to  roast  all  the  raw  ore  before 


I 

I 


R 

CI 


I 


« 


r 

e 
e 


I 


■  I 


kiMC  »TOMt 


Scale  of  Miles. 


Fig.  53. — Section  along  Cornwnll  Uailrond  from  Lebanon  to  Mincr'x  Village. 
After  E.   V.  (VlncillierH.  Amer.  Tnst.  mn.  Eng.,  XIV.,  898,  1880. 

smelting,  but  the  phosphorus  is  so  low  that  Bessemer  pig  is  the 
chief  resulting  product. 

Big  Hill  differs  from  the  others  in  structure.     The  northern 
dike  with  a  steep  southerly  dip  has  an   offsetting  and  very 
heavy  branch  to  the  southwest  which  forms  with   it  a  great 
trough  or  basin  so  far  as  one  can  see.     The  bottom  of  the  ore 
has  been  reached  by  one  rather  shallow  liole,  but  it  seems  quite 
certain  that  the  dikes  will  come  togetber  at  a  point  indicated  by 
the   several    dips.     The    surface   of  the   southerly   branch  is 
strongly    corrugated.     Tiie   ore   of   IVIiddle   Hill  extends  to  a 
greater  distance  south  from  the  dikes  than  that  of  Big  Hill,  and 
is  cut  by  one  small  and  unimportant  offset  of  trap  that  is  two  or 
three  feet  across.     At  the  western  end  of  the  workings,  lime- 


!.!1 


is  the 

orthern 
(1  very 
great 
the  ore 
IS  quite 
•atfMl  by 
ancli  is 
ids  to  H 
[ill,  and 
s  two  or 
rg,  lime- 


o 


i 


^ 


a 


£ 


v. 


00 

S 


S 

a 

o 

J- 


3 

6 


i;  I' 


178 


KEMP'S  CUE  DEPOSITS. 


% 


stone  is  quite  thick  and  in  good  exposure.  It  reaches  well  over 
to  Grassy  Hill.  Grass}'  Hill  is  smaller,  and  is  much  less  devel- 
oped than  either  of  the  others.  E.  V.  d'Invilliers  has  empha- 
sized the  important  point  that  the  dip  of  the  ore  in  Big  Hill  is 
southwest  at  such  an  angle  as  to  bring  it  below  the  Middlt; 
Hill  bed,  and  that  this  latter  also  dips  below  the  limestone  and 
the  Grassy  Hill  betls.  Such  being  the  case,  enormous  reserves 
must  lie  under  the  two  western  hills.  The  depth.*  of  the  sev- 
eral bore  holes  given  on  the  map  and  all  in  ore  indicate  its 
presence  in  very  great  amount,  but  it  is  important  to  show  in 
this  connection  the  absence  of  faults,  for  the  map  of  Bailey 
Willis  notes  their  presence,  and  observations  of  the  writer  eur- 
roborated  their  existence. 

The  pyrite  in  the  calcareous  shales  is  occasionally  replaced  by 
chalcopyrite  in  irregular  nodules  or  veinlets.  The  presence  of 
copper  was  early  noted,  and  some  mining  was  done  for  it  near 
the  surface.  Fine  museum  specimens  of  moss-copper,  a/uritc, 
malachite,  etc.,  were  afforded.  Even  during  the  earlier  iron- 
mining  some  copper  ore  was  set  aside  as  a  small  by-product. 
Copper  is  still  present  in  the  mine-water,  for  bright  shovels 
left  in  it  become  coated,  and  the  bones  of  dead  animals  thrown 
out  on  the  ore  banks,  as  well  as  chips  of  wood,  etc.,  become 
tinted  a  bright  green. 

Much  difference  of  opinion  has  prevailed  about  the  ago  and 
geological  relations  of  these  ores.  Some  have  thought  them 
Mesozoic  and  a  part  of  the  Triassic,  while  others,  and  notably 
J.  P.  Lesley,  have  regarded  them  as  belonging  to  the  Siluro- 
Canibriau  series  and  analogous  to  the  liniouites  of  the  Great 
Valley,  but  metamorphosed.  The  great  trap  dikes  afford  tlie 
most  reasonable  explanation  or  cause  of  the  change,  and  tKihen' 
may  be  referred  the  alteration.  The  apparent  origin  of  many 
Siluro-Cambrian  limonites  from  the  hydration  and  oxidation  of 
pyritous  shales  and  schiots  gives  much  support  to  this  view, 
and  the  association  of  limestone  with  the  ore  and  the  geiienil 
stratigraphical  relations  are  hard  to  explain  in  any  other  %vay.' 

'  E.  V.  d'Invilliers,  "  Cornwall  Iron  Ore  Mines,"  Trans.  Anicr.  Inst. 
Mill.  EiKj.,  XIV.,  878.  Ree.  Lesley  and  d'Invilliers,  Ann.  Rep.  Second 
Penn.  Gail  Sun-eij,  188.5,  4!il.  Ree.  J.  P.  Lesley,  Final  Rep..  I,  3S1.  18!)2. 
T.  S.  Hunt,  "Tlie  Cornwall  Mines,"  etc..  Trans.  Aincr.  Iiisf.  ^fiii.  EiiQ.. 
IV.,  yi9.  H.  D.  Rogers,  First  Penn.  Geo!  Siircei/,  II.,  718.  13.  Willis.  Tevlli 
Census,  XV.,  323. 


the 

tra 
niii 

otl 
iuh] 


le 


'  V 
\- 

VohU 

Siirr( 
<\iiii  /■ 

p.  m 

-Uiirr 
II..  71 


MAG N FAIT E  AND  PYItlTE. 


179 


The  total  productiou  to  April,  1804,  is  stated  by  Mr.  Boyd, 
the  superintendent  of  the  mines,  to  be  upward  of  ]  2,000,- 
000  tons,  while  an  annual  output  of  S00,000  can  be  easily  main- 
tained. The  ore  varies  from  40  to  b^%  Fe.  It  almost  never  con- 
tains as  much  as  O.Oa  P,  but  runs  up  to  A%  S.  It  is  also  sil- 
iceous. 

2.03.13.  Several  other  mines  of  somewhat  rUated  character 
to  the  Cornwall  deposits  are  known  along  the  edges  of  this 
Triassic  belt,  and  associated  with  its  trap  intrusions.  The 
niiuiug  districts  lie  near  its  north  and  south  boundaries,  and 
not  far  from  its  contacts  with  the  older  rocks.  On  the  north 
side  from  east  to  west  there  are  tlie  Boyertown  (Berks  Countj^), 
the  Fritz  Island  and  the  Wheatfield,  near  Reading,  and  finally 
the  Dillsburg  in  York  County,  west  of  tiie  Susquehanna.  On 
the  south  side  in  the  same  order  are  the  French  Creek,  St. 
Mary's  and  tlie  Jones,  all  quite  near  together  and  nearly  south 
of  Reading.  Of  these  the  Boyertown  mints  have  l)een  most 
worked.'  The  Cornwall  mines  are  between  the  Wheatfield  and 
the  Dillsburg.  At  the  Boyertown  mines  the  ore  lies  botli 
between  a  brecciated  limestone  and  Mesozoic  sandstone  and 
wholly  within  tiie  limeHtone,  but  trap  dikes  are  not  lacking.  At 
Fritz  Island  the  ore  is  entirely  enclosed  iti  limestone,  and  is 
penetrated  by  a  trap  dike.  In  the  Wheatfield  mines  the  same 
biecciated  limestone  appears,  and  has  the  ore  intimately  asso- 
ciated with  it.  On  both  occurs  the  Mesozoic  sandstone,  and 
the  succession  is  five  times  repeated  by  faulting.  The  usual 
trap  penetrates  the  ore.  The  French  Creek  and  St.  Mary's 
mines  are  uniipie  in  that  they  are  contained  in  gneiss.  They 
nrc  famous  sources  of  fine  crystals  of  pyrite,  chalcopyrite  and 
otlier  minerals.  The  Jones  mine  exhibits  the  ore  between  traj) 
and  limestone,  the  trap  being  over  the  ore  in  the  North  pit  aii<l 

'  P.  Fmser,  "  Study  of  tlie  Specular  .•itid  Tlomatite  Ores  of  Iron  of  tlie 
New  IJtHl  Sandstone  in  York  County,  Pa."  Trans.  Amcr.  In.st.  Mm.  Eik/., 
A',  V'Vi.  Also  Penn.  Geol.  Svrvei/.  Rep.  CC,  205,  21T.  H.  Hoefer,  "Die 
FohU'M  und  Eisenor7,lafj;fM-statt(Mi  Nord  .Aniorika's,"  241.  Also  Penn. 
Siinrii.  Rev.  C2.  K.  V.  dlnvilliers,  "Cornwall  Iron  Ore  Jlines,"  Traus. 
Amcr.  hist.  Mill.  Eiig.,  XTV..  87.3.  Reo.  Lesley  and  d'luvilliers,  Ann. 
Ri'i).  S,r,>n(I  Prim.  Siirre;/,  1885.  .1.  P.  Lesley,  Final  Rrport,  Vol.  L, 
P  Wl.  l,S!)2.  Ree.  T.  S.  TTunt.  "The  Cornwall  Jlines,"  etc,  Trans. 
Aiiirr  Inst.  Mill  Emj.,  IV.,  iUO.  H.  D.  Rogers.  First  Prim.  Geol.  Survey, 
n  .  TIM.    B.  Willis,  Tenth  Census.  Vol.  XV.,  p.  22:5.     Rec. 


■  t: 


:!ji!. 


\% 


180 


KEMP'S  ORE  DEPOSITS. 


under  it  in  the  south.  A  green  shale  is  also  met  here,  as  in- 
deed in  most  of  the  other  localities,  although  not  specially  men- 
tioned. At  Dillsburg  the  evidence  against  the  Triassic  age 
of  the  ores  is  leps  positive,  and  upon  this  occurrence  Fraser  has 
based  a  strong  argument  for  the  latter  view.  Triassic  sand- 
stone at  times  forms  both  walls,  although  there  are  instances 
where  limestone  appears  as  the  foot.  In  all  these  localities  the 
presence  of  copper  is  notable.  It  and  the  magnetic  or  metamor- 
phosed condition  of  the  ore  are  probably  referable  to  the  trap. 

2.03.14.  Example  \\a.  Iron  County,  Utah.  Beds  of  mag- 
netite and  hematite  bearing  evidence  of  being  metamorpiiosed 
limonite,  in  limestones  of  <]uestionable  Silurian  age,  and  asso- 
ciated with  eruptive  rocks  described  as  trachj'te.  The  lime- 
stones have  been  much  upturned,  metamorphosed,  and  pierc(^d 
by  dikes  and  eruptive  masses.  The  ore  forms  groat  projecting 
ridges  and  prominent  outcrops,  locally  called  "blow-outs." 
The  usual  lenticular  shape  is  not  lacking.  They  occur  over 
an  area  of  fifteen  by  five  miles,  and  are  in  the  soutliern  end  of 
the  Wasatch  Mountains.  The  samples  show  rich  ores,  which 
at  times  exceed  the  Bessemer  limit  of  phosphorus.  In  the  Star 
district  the  ore  api)arently  lies  between  the  quartzite  and  gi:an- 
ite.  Hematite  occurs  in  large  amount,  as  does  quartz,  while 
some  streaks  have  large  crystals  of  apatite.  The  importance 
of  the  deposits  lies  in  the  future.  They  are  the  largest  in  the 
West,  and  are  interesting  in  their  bearing  on  the  general  origin 
of  the  magnetite.  Coal,  not  proved  to  be  good  for  smelting,  is 
near,  but  centers  of  iron  consumption  are  \evy  far  away.' 

2.03.15.  Example  15.  Magnetite  sands.  Beds  of  magnetite 
sands  concentrated  on  beaches  or  bars  by  waves  and  streams. 
The  magnetite  has  been  derived  from  the  weathering  of  igne- 
ous and  metamorphic  rocks  through  which  it  is  every wiiere 
distributed.  When  in  the  sand  of  a  sea  beach,  it  and  other 
heavy  minerals  tend  to  become  concentrated  by  the  sortinc! 
action  of  the  waves.  They  resist  the  retreating  undertow  better 
than  lighter  materials.     Such  deposits   are  very  abundant  at 


'  W.  P.  Blake,  "Iron  Ore  Deposits  of  Soutliern  Utah,"  Trans.  Amer. 
Inst.  Miu.  Eng..  XIV.,  809.  ,T.  S.  Newberry,  "(Jenesis  of  Our  Iron  Ores," 
ScJiool  of  Mines  Qnartevly,  March,  1880.  Reo.  Ein/inecriitg  and  Mining 
Journal,  April  23,1881,  p.  286;  Proc.  National  Academy,  1880.  B.  T. 
Putnam,  Tenth  Census,  Vol.  XV.,  486.     Rec. 


MAONKTWh:  ANl>  PVIilTE. 


181 


Moisie,  on  the  St.  Lawrence,  below  Quebec,  and  in  the  United 
States  are  known  in  smaller  developments  on  Lake  Champlain; 
at  Quogue,  L.  L;  on  Block  Island;  in  Connecticut;  along  the 
Great  Lakes,  and  on  the  Pacific  coast.  Grains  of  garnet,  oli- 
vine, hornblende,  etc.,  minerals  of  high  specific  gravity,  are 
also  in  the  sands.  Many  are  too  high  in  titanium  to  be  of  use, 
liut  there  is  no  more  difficulty  in  their  concentration  than  in 
that  of  artificially  crushed,  ore.  In  Brazil  and  New  Zealand 
they  have  attracted  attention.' 

•v>.0.'{.l(>.  On  the  Origin  of  Magnetite  Deposits.  It  is  im- 
portant to  note  that  magnetite  deposits  are  almost  always  in 
nietamorphic  rocks,  which  owe  their  character  to  regional 
nietamorphism  or  to  the  neighborhood  of  igneous  rocks  (Penn- 
sylvania and  Utah)-  Gneisses  form  the  conmionest  walls,  but 
so-called  norites,  or  gabbros,  and  crystalline  limestones  also 
contain  them.  Where  there  is  lamination  or  foliation  the  mag- 
netite conforms  to  it.  As  the  history  of  the  nietamorphic  rocks 
is  so  often  uncertain,  the  magnetites  share  the  same  doubt. 
In  igneous  rocks  magnetite  is  the  most  widely  occurring  of 
the  rock-making  minerals.  In  all  explanations  the  prevailing 
lenticular  shape,  the  general  arrangement  in  linear  order,  and 
the  existence  of  great  beds  must  be  considered.  The  shape  is 
very  similar  to  that  of  deposits  of  specular  hematite,  with 
which  magnetite  is  often  associated.  (Exam])les  9  and  10.) 
The  following  hypotheses  have  been  advanced  for  the  origin  of 
magnetites:  1.  Intruded  (eruptive)  masses.  This  supposes 
that  the  lenses  have  been  intruded  like  a  trap  dike,  and  have 
then  been  st^ueezed  and  pinched  apart.  Though  formerly  much 
advocated,  it  is  now  generally  rejected.  2.  Excessively  basic 
portions  of  igneous  rocks.  This  supposes  that  large  amounts 
of  iron  oxide  have  separated  in  the  cooling  and  crystallizing  of 
basic  magmas.  There  are  such  occurrences,  although  seldom, 
if  ever,  pure  enough  or  abundant  enough  for  mining.  The 
titauiferous  magnetite  of  the  Minnesota  gabhros  has  been 
alluded  to  (2.02.25),  and  also  the  Brazilian  ore  and  the  Cum- 

'  T.  y.  Hunt,  Geol.  Survey,  Canada,  lH()0-(59,  !2Gl,  263;  quoted  in  Six 
tvenihAnn.  Rep.  Dir.  U.  S.  Geol.  Stiroey.  III.,  .W,  51;  Can.  Nat.,  VI.,  79 
A.  A.  Julien,  "The  Genesis  of  tlie  Crystalline  Iron  Ores,"  Acad  Xat.  Set.. 
Phila.,  1882,  335;  Engineering  aiid  Mining  Journal,  February  2,  1884.  On 
New  Zwiland  sands,  E.  M.  Smith,  Proc.  Brit.  Iron  and  Steel  Inst.,  May, 
1896;  Eiuj.  and  Miu,  Jour.,  Ju  ie  13,  1896,  p.  566. 


i'l'i 

I'   ft 


i8d 


KhJ}fP'S  ORE  DEPOSITS. 


berland  Hill    (R.  I.)   peridotite.      Should  such   igneous  rocka 
be  subjected  to   regional   nietamorphism   and. the  stretching 
action  cliaracteristic   of  it,  the  ore  masses  might   be  drawn 
out  into  lenses.     3.  Metamorphosed  limouite  beds.     This  idea 
has  been   most  widely  accepted    in   the  past.     It  presupposes 
limonite  beds  formed  as  in   Examples  1  and  2,  which  become 
buried  and  subjected  to  metamorphism,  changing  the  ore  to 
magnetite,  and  the  walls  to  schiyts  and  gneisses.    Igneous  rocks 
have  apparently  changed  limonites  to  magnetite  at  Cornwall, 
Pa.,  and  in   Utah,   but  such  changes  by   regional  metamor- 
phism are  lesh  easy  to  demonstrate.     The  limonite  may  have 
resulted  from  the  oxidation  of  lenses  of  pyrite.     4.  Replaced 
limestone     beds,    or    siderite     beds    subsequently     metamor- 
phosed.    Such   deposits  may  pass  through  a  limonite  stage. 
The  general  process  is  outlined  under  Example  Oc,  as  devel- 
oped by  Irving  and  Van   Hise  in  the  Gogebic  district.     The 
lenticular  deposits  of  siderito  at  the   Burden  mines  (Example 
4)  are  very  suggestive,  and  some  such  original  mass  migiit  iu 
instances  be  metamorphosed  to  magnetite.    5.  Submarine  chem- 
ical precipitates.  This  is  outlined  under  Example  9d,  as  applied 
by  the  Winchells  in  Minnesota.     <5.  Beach  sands.     The  lenses 
are  regarded  as  having  been  formed  as  outlined  under  Exam- 
ple 15.     The  same  heavy  minerals  sometimes  occur  with  maj,^- 
netite  lenses  as  are  found  on   beaches."     7.  River  bars.     Tliis 
regards  the  lenses  as  due  to  the  concentration  of  magnetite 
sands  in  rivers  or  flowing  currents.     Hence  the  overlapping 
lenses,  the   arrangement  in  ranges  or  on  lines  of  drainage, 
and  the  occasional  swirling  curves  found  on  the  feathering 
edges  of  lenses,  as  in  the  Dickerson  mine,  Ferromont,  N.  J.' 
It  is  also  reasonable  to  suppose  that  lakes  or  still  bodies  of  water 
may  have  occurred  along  such  rivers,  and  have  occasioned  tlie 
accumulation.     S.  Segregated  veins.     By  this  method  the  iron 
oxide  is  conceived  to  concentrate  from  a  state  of  dissemiuatien 
in  the  walls  by  slow  segregation  in  solution  to  form  the  ore  bodies 
along  favorable  beds.  The  action  is  analogous  to  the  formation 
of  concretions,  and   is  illustrated  on  a  small  scale  by  the   woll- 

'  See  also  Dakj-ns  and  Teall,  Quar.  Jour.  Oeol.  Soc,  LXVIII.,  p.  118. 

"  See  B.  J.  Harrington,  Can.  Geol.  Survey,  1873,  193;  A.  A.  Jnlien, 
Phila.  Acad  Sa.,  1S82,  885. 

'  See  H.  8.  Muuroe,  School  of  Mines  Quarterly,  Vol.  III.,  p.  43— an  im- 
portant paper. 


MAON/'JTITE  AND  PYRITE. 


183 


known  disks  of  pyrite,  or  of  siderite,  that  form  in  clays  and 
shales.  It  is  a  curious  fact,  however,  that  some  magnetites  are 
iu  wall  rock  that  hardly  sliows  a  trace  of  a  dark  silicate.  The 
lenses  at  Hainiiiondville,  in  the  Lake  Clianiplain  district,  are 
iu  a  white,  or  light-colored  gneissoid  rock,  consisting  of 
(|iiartz,  acidic  plagioclase,  and  a  few  scattered  garnets.  In 
Hiich  surroundings  segregation  could  not  be  applied,  hut  where 
the  walls  are  supplied  with  hornblende  and  other  ferruginous 
minerals,  and  are  reasonably  basic,  it  might  be  advocated. 

Several  other  hypotheses  with  small  claims  to  credibility 
could  be  cited.  They  are  outlined  at  length  in  Bidl.  VI. ^ 
Minn.  Ueol.  Survey,  p.  224,  but  in  this  place  there  has  been 
uo  de^iire  to  take  up  any  but  those  deserving  serious  attention. 
It  may  be  said  that  while  one  or  the  other  of  the  above  seven 
hypotheses  may  in  instances  be  applied  with  reason,  yet  most 
candid  observers  with  widened  experience  have  grown  less 
positive  in  asserting  them  as  axiomatic. 


ANALYSES  OF  MAGNETITES. 

(Caution  in  interpreting  analyses  is  again  enipli.asized  as  under  3.01.26.) 


Fe. 

P. 

S. 

TiO,. 

HiO,. 

Al,03. 

Caiiuda  (Kideau  t'aual) 

Cliateauguy  mines,  N.  Y.,  lump. . 
concentrated. 

Mineville,  N.  Y.  (Mine  21) 

Orange  County,  N.  Y.   (Forest  of 
Dfiiu) 

50.23 
49.24 
(SO  00 
62.10 

(53.00 
4S.82 
.53.75 
42  70 

0.02!) 
0.003 
1.1U8 

0.02t 
0  (»2t 
0.364 
0.135 
0.004 
0.026 
0.044 

'0.053 

9.80 

18.447 

0.148 
0.080 

Put  nam  County,  N.  Y 

New  Jersey  (Hibernia) 

rornwall,  Pa  . .              

11.75 

3.500 

0.630 
0.115 

3.411 

(  ranl)erry,  N.  C    64.64 

Colorailo  (Calumet) 

"         firon  Kintr^ 

45).  23 

.58.75 

3.85 

0.123 
0.120 

Utiili  (Iron  County) 

Calit'oruia  (Gold  Valley) 

63.00 
60.08 

4.80 
10.87 



2.03.10.  Of  importance  in  connection  with  iron  ore  deposits 
are  tiie  recent  studies  of  the  distribution  of  phosphorus  along 
certain  lines  in  the  beds,  by  a  knowledge  of  which  it  is  possi- 
ble to  keep  more  valuable  Bessemer  ore  distinct  from  less 
valuable.  Such  lines  have  been  found  in  Michigan,  and  have 
been  called  by  D.  H.  Browne  "isochemic  lines."    Though  less 


1^ 


184 


Kh'Ml'S  OUK  DhPOSlTS. 


marked  at  tlie  Burden  iniiioa  (Example  '\),  tlio  phoHphorus  was 
chara(!teriHti(i  of  cortaiu  variotios  v(  tlie  ore.  iMiicb  work  has 
hIhu  beeu  doue  on  the  Hanie  (pieHtion  at  Iruu  Mountain,  Mo.' 

P  Y  KITE. 

2.();5.17.  Example  Ki.  riirito  licds.  Keds  (veins)  of  pyrite, 
often  of  lenticular  .shape  and  of  character  frecjuently  analogous 
to  nuiguetite  deposits,  in  slates  and  schists  of  the  Canihro- 
Silurian  or  Huronian  systems,  and  less  often  in  gneiss  of  the 
Archean.  Slates  are  most  common,  and  gneiss  least  so.  They 
extend  from  (^anada  down  the  Ajipalachiaus  to  Alahania,  being 
found  at  (.*a})eltoii,  Quebec;  Milan,  N.  H. ;  Vershire,  Vt. ; 
Charlemont,  Mass.;  Louisa  County,  Virginia;  Ducktowu, 
Tenn.,  and  at  many  points  less  well-known  in  Alabama. 
Anthony's  Nose,  N.  Y.,  the  Gap  mine,  Pennsylvania,  and 
Sudhury,  Ontario,  being  different  geological  relations,  will  be 
mentioned  under  "Nickel"  with  other  similar  occurrences. 

2.();{.  IS.  The  ore  bodies  lie  interfoliated  in  the  slates  or  schists, 
and  the  different  lenses  often  overlap  and  succeed  each  other  in 
the  footwall,  and  exhibit  all  the  phenomena  cited  under  magne- 
tites. Chalcopyrite  is  usually  present  in  small  amount,  and 
where  the  copper  reaches  '.\  to  o*'o  they  are  valuable  as  copper 
ores.  (See  under  "Cojiper.")  At  present  they  are  of  increas- 
ing importance  as  a  source  of  sulphuric  acid  fumes  for  the 
manufacture  of  vitriol.  Small  amounts  of  lead  and  zinc 
sulphide  are  often  present,  and  rarelj'  a  little  silver.  Nickel 
and  cobalt  occur,  especially  in  the  pyrrhotitic  varieties.  They 
are  worthless  as  a  source  of  iron.  The  smaller  deposits  of 
auriferous  pyrites  in  the  Southern  States  will  be  mentioned 
under  "Gold." 

'Z.O'.^.Y,).  Some  pyrites  lenses  may  have  accumulated  in  a  way 
analogous  to  the  bog  ore  hy})otbesis,  cited  under  "Magnetite"; 
but  instead  of  the  iron  being  precipitated  as  oxide,  it  has  proba- 
bly come  down  as  sulphide  from  the  influence  of  decaying  or- 
ganic matter,  and  has  subsec^uently  shared  in  the  metamorphisra 
and  solidification  of  the  wall  rock.    At  the  same  time  it  must  be 

'  D.  H.  Browne,  "  On  the  Distribution  of  Pliospliorus  at  the  LiuUliiijj;tou 
Mines,"  etc.,  Trtr U.S.  Amer.  Inat.  Min.  Eng.,  XVII.,  p.  (ilO.  I.  Ohnstfii, 
"Tlie  Distribution  of  I'liosi)li()rus  in  the  Hudson  Hiver  Carbonates," 
Tmnx.  Awn:  Inxf.  Min.  Eikj..  XVIII.,  p.  2."i3.  W.  B.  Potter,  "Analysis  of 
Mi.ssouri  Ore,"  imblished  in  Miiund  Ri'sonri-cs,  IHIC),  j».  47. 


MAHNhyi'lTIC  AM)  I'yiilTK. 


185 


admitted  to  be  an  obHCure  point.  By  many  they  are  tlionj^lit, 
with  more  reawon,  to  have  originated  like  a  be(i(ied  tiHsure  vnin 
wlioHO  overlapping  h^ntiotilar  oavitieH  liave  heen  formed  by  tho 
biKJkliiig  offolded  HohiHtw.'  (Cf.  "(icild  Quartz,"  as  later  do- 
Hcribed.)  Tho  Diicktown  veina  are  on  linoH  of  dislocation  be- 
yond (juestion.  Replacements  of  pinched  bedn  of  limestone  are 
aiwayn  to  be  considered,  and  the  presence  of  intruded  dikes, 
though  disguised  by  nietamorphism.  ia  ahvaya  to  be  kept  iu 
mind. 

•.*.o;{."^().  The  excavations  in  some  of  the  minea  in  the  pyrite 
bods  of  Canada,  just  north  of  the  Vermont  line,  have  shown 
dikes  of  granite  in  close  association  with  the  ore.  Thin 
sections  of  the  granite  indicate  that  it  has  suffered  extremely 
severe  dynamic  nietamorphism,  for  crushed  and  strained 
crystals  make  up  nearly  all  of  its  substance.  It  is  (juite 
|)robal)le  that  the  disturbance  which  causes  the  schiatosity 
or  slaty  cleavage  of  the  country  rock  likewise  developed  the 
strains  in  the  granite  which  must  thus  have  been  intruded  pre- 
vious to  its  operation.  Before  the  shattering  the  dikes  may 
have  exerted  a  genetic  influence  in  connection  with  the  ore 
body,  but  now  the  ore  is  usually  lean  near  them.  The  ore 
bodies  are  also  cut  by  tine  examples  of  the  trap  (camptonite) 
dikes  which  are  abundant  in  the  Lake  Champlain  Valley. 
Prof.  J.  H.  L.  Vogt,  of  Christ iania,  Norway,  has  written 
of  late  regarding  the  origin  of  similar  great  bodies  of  sulphides 
iu  Europe,  and  when    they  occur  in  connection  with  rocks, 

'  \V.  H.  Adams,  "Tlie  Pyrites  Deposits  of  Louisa  County,  Virginia," 
rmiiH.  Anu'i:  hist.  Miii.  Eikj.,  XU.,  p.  M7.  C.  R.  Boyd,  "Tlie  Utiliza- 
tion of  the  Iron  and  Copj)er  Suipliides  of  Virginia,  North  Carolina,  and 
Tennessee,"  Trans.  Ainer.  lust.  Miii.  Eiig.,  XIV.,  p.  81 ;  Resources  of  S.  W, 
Virfiiiiid.  H.  Credner,  "At  St.  Anthony's  Nose,  Hudson  River,"  B.  iiud 
II.  /(it.,  18(56,  p.  17;  "Pyrite  in  Virginia,  Tennessee,  and  (Jeorgia,"  B.  nnd 
n.  Zrit.,  1871,  p.  870.  H.  T  Davis,  Mineral  Iiesonrc.es  of  ttie  U.  S.,  188."), 
p.ridl.  William  Martyn,  Mnem/  Resourcc.%  1883-84.  p.  877.  E.  C.  Mox- 
liani,  "The  Great  Gossan  Lead  of  Vn-ginia "  (altered  pyrite  in  Carroll 
County),  Trans.  Amer.  Inst.  j\Iin.  Emj.,  XXL,  p.  i;?3.  A.  F.  Wendt, 
"The  Pyrites  Deposits  of  the  Alleghanies,"  School  of  Mines  Quar- 
tcrlj/.  Vol.,  VIL,  and  sei)anite  reprint;  also  Encfineering  and  Alining 
'lounml  June  5,  1886,  p.  2'i,  and  elsewhere.  Kec.  H.  A.  Wheeler, 
"Cop])er  Deposits  of  Vermont,"  School  of  Mines  Quarterly,  IV.,  310. 
Artimr  Winsiow,  "Pyrites  Deposits  of  North  Carolina,"  Ann.  Rept.  N.  C. 
Kcperiincnt  Station,  1886. 


186 


KEMP'S  ORE  DEPOSITS. 


which  though  now  gneissoid,  have  been  originally  igneous,  he 
regards  them  as  basic  segregations  of  an  igneous  magma.  (See 
further  l.OO.Kl.)  Where  they  oCcur  in  schists  he  attributes 
their  formation  to  ore-bearing  solutions,  penetrating  along 
planes  of  weakness,  and  stimulated  by  neighboring  igneous 
intrusions.  In  some  of  the  instances  cited  tlie  known  igneous 
intrusions  (as  at  Ranimelsberg)  are  at  some  distance,  and  thus 
are  not  directly  associated,  so  far  as  one  can  see,  with  the  ore. 
The  genetic  connection  is  therefore  somewhat  hypothetical. 


2.03.21.  The  relative  importance  of  the  different  kinds  of 
ore  is  shown  by  the  following  tables  for  1S80  and  189(5.  The 
increase  in  red  hematite  is  due  to  the  Lake  Superior  region, 
and  to  Alabama.  In  tlie  immediate  future  the  soft  ores  of  tlio 
Mesabi  district  will  help  to  greatly  swell  the  total,  but  during 
1803-94  there  was  great  depression  in  the  mining  ol  iron  ore 
throughout  the  country : 


1880. 


Red  hematite 2,r)12,712 

Magnetite 2,;{no,889 

Ihown  hematite 2,14i),4l7 

Carbonate 923,288 


7,974.806 


Per  cent. 

Per  cent. 

of  Totiil. 

1896. 

of  Total. 

31.51 

12,570,288 

78.r,s 

29.98 

1,211,526 

7.57 

20. '.15 

2,120,213 

]:i.28 

11.50 

91,423 

0.57 

iOO.OO         16,005,449        100.00 


As  indicating  the  lelative  importance  of  the  different  mining 
regions,  the  following  figures  are  of  interest.  No  individual 
State  pioducing  less  than  100,000  tons  is  given. 


states.  Total  in  1896. 

Michigan 5,700,7:56 

Minnesota 4,283,880 

Alabama 2,041,793 

Virfrinia 859.406 

Pennsylvania 747,784 

Wisconsin 607,405 


states.  Total  in  ISiXi 

Ten  nessee 5:55, 484 

New  York 385.477 

New  Jersey 20i!l!)it 

Colorado 215,819 

Ceor^ia and  N.  Carolina      175.:i:U 

All  the  others 181,275 


Grand  total 16,005,449 

2.0.3.22.  Note.  Large  quantities  of  excellent  Bessemer 
hematite  are  shipped  to  Baltimore  and  other  Atlantic  ports 
from  the  mines  on  the  southeastern  coast  of  Cuba,  in  the  Jiira- 
gua  Hills.     Santiaj^j  de  Cuba  is  the  largest  town   in  thit* 


MAGNETITE  AND  PYRITE.  187 

region,  and  is  some  twenty  miles  west  of  the  mines.  The  coast 
rauge  of  hills  consists  mainly  of  syc  lite,  according  to  J.  P. 
Kimball,  and  the  syenite  is  penetrated  by  many  dikes  and  is 
raiiiitled  by  sheets  of  diorite  with  which  the  ores  are  associated. 
Kimball  refers  the  precipitation  of  much  of  the  iron  oxide 
which  came  from  the  diorite  to  coraline  limestone,  which  bad 
been  accumulated  as  coral  reefs  on  the  syenite  before  the 
diorite  was  intruded,  but  be  al?^  mentions  other  deposits  in 
the  diorite  not  associated  vvitb.  ".iiestone.  From  observations 
of  another  group  of  ores  sixteen  miles  east  of  those  studied  by 
Kimball,  F.  F.  Chisholm  reached  a  different  conclusion  regard- 
ing their  origin.  Chishohn  refers  them  to  a  source  below  and 
apparently  regarded  them  as  veins  or  rei)lacements  of  dikes. 
The  amount  of  ore  along  this  coast,  both  in  place  and  as  float 
is  very  great,'  and  will  be  an  important  feeder  to  American 
furnaces.  Between  three  and  four  hundred  thousand  tons  are 
now  annually  imported.  Chisholm  gives  the  following 
analyses : 

Fe.  S.  P. 

Juragua  ( Kimball) 64.(55  0 .146  0.037 

SiKiui  ((ilrahain) H4.00  0.040  0.016 

Berraco  (e'liLsliolm) 60.00  0.037  0.027 

Although  not  a  eource  of  supply  for  American  furnaces,  it  is 
interesting  to  note  in  this  connection  that  in  Mexico  vast  depos- 
its of  hematite  and  martite  occur  in  Cretaceous  limestone  asso- 
ciated with  intrusions  of  diorite.  The  paper  of  R.  T.  Hill 
cited  below  gives  a  review  and  full  bibliography  of  the  various 
localities.  The  notable  deposits  so  far  as  yet  opened  up  are  at 
the  Cerro  de  Mercado,  in  Durango,^  the  Sierra  de  Mercado, 

'  J.  P.  Kimball,  "  Geological  Relatious  and  (leuesis  of  the  Specular  Iron 
Ores  of  Santiago  tie  Cuba,"  Amcr.  Join:  Sei.,  December,  18!S4,  p,  416;  also 
"Tlie  Iron  Ore  Kaiige  of  tlie  Santiago  District  of  Cuba,"  Triins.  Antir. 
Iiiat.  Mill.  Eiig.,  Xlll.,  6i;5;  Emj.  and  Miii.  Join:,  December  30,  1884.  p. 
4iii».  F.  F.  Cliisliobu,  "  Iron  Ore  Reds  in  tbe  Province  of  Santiago,  Cuba," 
Prm:  Volo.  Sci.  Soc,  III.,  2')d,  1M90.  II.  Wedding,  "Die  Eisenerze  der 
Insel  Cuba,"  Stahl  and  Eiiten.  18!)3.  No.  12.  Prof.  J.  W.  Sfieucer  has  been 
recently  working  on  tiie  geology  of  ( "uba  and  i)resented  .some  of  his  results 
at  llie  iMceting  of  tiie  Anieriean  A.ssoeiation  in  Brooklyn,  August,  1894. 

'  .).  Birkinbine,  'Tlie  Cerro  de  Merrado  or  Iron  Mountiiin  of  Durango," 
TraiiN.  Amcr.  Inst.  Min.  Eikj..  Xlll.,  181.,  1H84.  J.  P.  Carson,  "Iron 
Miuiufactnre  in  Mexico.  '  Hem.  VI.,  :599.     R.  T.  Hill,  "The  Occurrence  of 


188 


KEMPS  ORE  DEPOSITS. 


near  Monclova  in  Coahuila/  and  others  of  minor  importance 
in  the  States  of  Jalisco,^  Guerrero^  and  elsewhere.  Several  of 
these  are  now  the  basis  of  a  small  local  smelting  industry. 

Hematite  and  Martite  Iron  Ores  in  Mexico,"  ^Imer.  Jour,  ^'ci.,  February, 
1893,  111.  B.  Sillinian,  "Martite  of  the  Cerro  cle  Mercado,  or  Iron  Mouu- 
tain  of  Durangc,  and  Certain  Iron  Ores  of  Sinai oa,"  Amer.  Jour.  Sci., 
November,  1883,  375.  See  also  on  the  Durango  Iron  ]\Ioinitain,  Annales  del 
Ministerio  cle  Fomento  de  la  Pep.  Mexicana  Toino,  III.,  1877;  Eng.  and 
Min.  Jour,  on  "Iron  in  Mexico, " November  10,  1888,  p.  391. 

'  P.  Frazer,  "  Certain  Silver  and  Iron  Mines  in  the  States  of  Niieva 
Leon  and  Coahuila,  Mex.,"  Trans.  Amer.  Inst.  Min.  Eng.,  XII.,  537.  R. 
T.  Hill,  as  cited  in  previous  footnote. 

•  J.  P.  Carson,  as  cited  in  second  footnote. 

'  N.  S.  l\Ianross,  "Notes  on  Coal  and  Iron  Ores  in  State  of  Guerrero, 
Max.,  Amier.  Jour.  Sci.,  May,  1865,  p.  309;  Remarks  by  J.  D.  Dana,  p.  358. 


CHAPTER  IV. 

COPPER. 

2.04.01.     Copper  Ores. 

TABLE  OF  ANALYSES. 


Ou. 


Native  copper  (generally  with  some  silver) 100. 00 

C'halcocite,  Cu,S '. 79.80 

Ciiak-opyrite,  CuFeSj 34.00 

Bdiiiite.  CuaFeSg 61 . 79 

THniiiedrite,  4CuS„,  Sb^S., (variable)  26.50  Sb, . .  36.40 

Eimrgite,  CU3ASS4  (As,  19. 1) 48.40 

Cu|)riti>.  CUgO 88.80 

Mt'liiw)7iite  (tenorite),  CuO 79.86 

Maiiiohite,  SCuOCOs,  HgO 40.28 

Azurite,  lU'iiOCOg.  HgO 46.31 

Cluy.socoUa.  CuO.SiOg,  2HsO. 22 . 06 


S. 

20.2 
34.9 

2r).8 

26.7 
32.5 


Fe. 


30.. 50 

11.70 

1.3f> 


2.04.02.      Example    10,  Continued.      Pyrite    or    pyrrliotite 

beds  (veins),  with   intermingled    chah.'opyrite.     Whether  the 

deposits  are  tme  beds  or  veins  parallel  with  the  foliation,  is  as 

yet  a  matter  of  dispute.     The  resemblance  to  magnetite  sug- 

f^ests  a   bed,  and   this   view   is  generally  taken   by  German 

writers.     The  California  mines  occur  closely  associated  with 

the   auriferous  (pyritous)   quartz    bodies,  which    are    always' 

'>tpemed   veins.     But  as  detailed   knowledge   increases,  it   is 

lure  and  more  appreciated  that  the  ore  bodies  are  mostly  if 

I  t  entirely  veins  «nd  have  been  deposited  along  lines  of  dis- 

ocatiun.' 

Pyrites  and  pyirhotite  (called  mundic  by  the  miners)  are  the 
inincipMl  constituents  of  such  bodies,  but  often  the  copper 
riaches '^i  5  to 5'-,,',  and  then  they  are  valuable  for  copper.  There 

'  Compare  in  this  connection  .J   H    L.  Vogt,  "  Ueber  die  KiesiaKerstJit 
ten  v()i\  'lyinis  Roros  Vip;.sniis.  Sulitelma  in  Xorwegen  und  Kaninielsberg 
ill  t'eutseliiand,"  Zeitschr  fi'ir  prakt.  Gealo(jie,  February,  April  and  May, 


!    'i 


TOO 


KEMP'S  ORE  DEPOSITS. 


is  quite  a  characteristic  group  of  minerals  that  is  associated 
with  the  ores.  Zinc  hlende  is  almost  always  present  in  small 
quantities,  and  is  a  cjreat  drawback  to  the  ore  when  employed 
for  acid.  Galena  is  met  in  traces.  Quartz,  calcite,  some  forn) 
of  amphibole,  and  often  very  beautiful  garnets  are  associated. 
Ducktown  is  noted  for  its  zoisite.  All  the  secondary  minerals 
of  the  oxidized  zones  of  sulphides  are  met.  The  ores  are  often 
roasted  for  sulphiu-ous  fumes  in  acid  works,  and  afterward  the 
residues  are  shipped  to  the  copper  smelters.  The  mines  have 
been  or  are  being  worked  for  cop{)er  near  Sherbrooke,  and  at  a 
great  number  of  other  points  in  Quebec,  just  north  of  Vermont. 
There  are  also  not  a  few  localities  in  Maine,  New  Brunswick, 
Nova  Scotia  and  Newfoundland,  where  operations  of  a  more  or 
less  serious  nature  have  been  undertaken.  Citations  to  the 
literature  regarding  these  will  be  foiuid  at  the  close  of  the 
description  of  Ducktown.  At  ]\Iilan,  N.  H.,  there  are  several 
deposits  in  argillitic  schists,  and  in  the  same  region  there  are 
numerous  other  locations.  At  Vershire,  Vt.,  there  is  a  belt 
some  twenty  miles  long,  with  three  principal  mining  point*. 
Of  these  the  middle  one,  containing  the  Ely  mine,  is  the 
.'argest.  Two  beds  of  ore  occur,  separated  by  from  10  to  'JO 
feet  of  schists.  The  lower  averages  about  four  feet,  but  tluc- 
tuates;  the  upper  is  still  more  variable,  and  may  reach  2.')  feet. 
They  are  botli  formed  by  a  succession  of  thin  lenses.  The  ore 
is  chalcopyrite,  mingled  with  pyrrhotite  and  quartz. 

2.04.0.'}.  More  complete  observations  are  available  upon  the 
Ducktown,  Tenn.,  deposits,  than  upon  any  others  of  the  type  in 
America.  The  excellent  paper  by  Carl  Henrich  is  here  spe- 
cially drawn  upon  and  has  been  supplemented  by  some  few  fur- 
ther notes  hy  the  writer.  Ducktown  is  situated  in  the  south- 
eastern t(nvuship  of  Tennessee,  and  occupies  a  small  plateau 
between  bounding  ranges  of  higher  mountains.  The  plateau 
has  been  much  dissected  by  the  [)resent  drainage,  but  its  stunii)- 
remain,  and  serve  to  indicate  the  peneplain  of  Tertiary  date,' 
The  country  rock  is  mica  schist,  with  occasional  heavier  h&h 
that  tend  toward  cjuartzite  or  even  gneiss.  Some  hornbleiidic 
rocks  are  present  with  the  ores,  but  whether  they  represent  in- 
truded dikes  as  suggested  by  Henrich,  or  streaks  of  silioeons 

'  C.  W.  Hayes,  "  ( leomorphology  of  tlie  Hoiitlmru   Aj)palat;liiaii>.    •^" 
tional  Geographic  Magazine,  VI.,  68,  18i)4. 


Fig.  2. 


MAP  OJF  THE  OUCKTOWN    MINES. 

Fig.  So.  —  .]f(ip  oft/n  mims  a  ml  of  the  outcrop  of  gotmiui,  s/ioiHiif/  l/ic  relations 

and  extent  of  the  eeiiin  at  Dui'ktowii,  Tenn.     After  Carl  llenrich. 

Trans.  Amer.  Inst.  Min.  Kng.,  XXV,,  178,  1895. 


192 


KEMP'S  ORE  DEPOSITS. 


limestone,  it  is  not  possible  to  determine.  The  schists  are 
metamorphosed  shales,  and  the  schistosity  appears  to  be  gener- 
ally parallel  to  the  original  bedding.  The  geological  age  is 
still  in  dispute,  but  is  probably  Pre-Carabrian. 

The  schists  strike  N,  20-25  E.,  and  have  a  prevailing  dip  of 
about  50  to  55  S.  E.  There  are  variations  of  the  latter  which 
are  due  to  rolls  and  faults.  The  schists  have  been  broken  by 
dislocations  along  which  the  ores  have  been  deposited.  The 
strike  of  the  ore  is  parallel  to  the  strike  of  the  schists,  and  the 
dip  is,  as  a  rule,  the  same  as  that  of  the  schists,  but  cases  have 
been  observed  where  the  ores  cut  the  dip  of  the  country  rock,  al- 
though with  such  soft  and  easily  mashed  materials  it  is  diffi- 
cult to  identify  the  unconformity.  There  are  two  principal 
belts  of  fracture  as  shown  by  the  map,  Fig.  55,  and  probably 
several  minor  ones,  between.  The  Old  Tennessee,  Burra  Burra, 
London  and  East  Tennessee  lie  along  the  northwest  belt;  the 
Polk  County,  Mary,  and  Calloway  form  the  southeast  belt; 
and  the  Culchote  and  Isabella  lie  in  tlie  interval.  The  ore 
bodies  are  huge  lenticular  masses  of  sulphides,  which  probably 
owe  this  shape,  as  far  as  it  is  at  all  discernible,  to  diagonal 
faulting  since  the  veins  were  filled.  The  common  ore  is  an 
aggregate  of  pyrrhotite,  chalcopyrito.  calcite,  (juartz,  zoisite, 
and  in  some  mines  much  actinolite.  Zinc  blende  and  galena 
are  present,  but  are  insignificant.  Garnets  are  occasionally  met 
in  quantity.  On  some  of  the  claims  pyrites  is  abimdant,  as  in 
the  Burra  Burra,  and,  as  is  reported  to  be  the  case  nt  the  Isa- 
bella, it  taking  the  place  of  the  pyrrhotite  to  a  greater  or  less 
degree.  The  content  of  copper  varies  up  to  .3,5/o,  with 
occasional  bunches  that  run  higher.  The  old  black  copper  ores 
tliat  accumulated  at  the  water-level  are  now  exhausted.  (See 
Fig.  5(J.)  From  observations  on  the  succession  and  charactpr  of 
the  minerals  in  the  vein,  J.  F.  Kemp  has  drawn  the  followiiig 
conclusions  regarding  the  geological  history  of  the  veins.  By 
a  process  of  rtgioual  metamorphism,  a  sedimentary  series  of 
shales  and  sandstones  was  altered  to  mica  schists  and  quartz 
schists.  Where  the  ore  is  now  found,  zoisite,  tremolite,  i\m\ 
garnet  were  also  produced,  but  it  is  not  known  whether  they 
are  met  outside  of  the  mines  or  not.  They  indicate  the  former 
presence  of  magnesian  fuid  cnlcareons  rocks,  although,  gener- 
ally speaking,  lime  is  practically  unknown  in  the  metamorjihic 


COPPEJt. 


193 


rocks  of  the  district  and  tlio  l(x;al  waters  are  remarkably  pure 
iiiul  soft.  Whether  a  calcareous  shale  or  an  intruded  dike 
j'ielded  the  lime  silicates,  or  whether  they  are  metamorphosed, 
calcareous,  vein  material  from  an  older  vein  filling  cannot  be 
stated.  After  the  gen(>ral  tnetamorphism,  a  series  of  disloca- 
tions was  developed  along  the  lines  of  the  present  veins,  and 


Cross-Section  A-A.  (Fig.  8.) 
Shaft  3.  Old  Tennessee  Mine, 


5  in 


30      in 


75 
_J_ 


100  Feet 


100 


FlQ.  56. — Cross-section,  S/nift '^,  Old  Tennessee  Mine,  Dttcktown,  Tenn.,  show- 

iitf/  ike  (/omi.ii,  the  black  ore,  t/ie  piirrhntite  and  a  fault.     After  Carl 

JJenncli,  Trans.  Amcr.  Inst.  Min.  Kmj.,  XXV.,  198,  1895. 

pyrrhotite  and  sometimes  pyrite  were  introduced.  After  the 
dejiosition  of  the  pyrrhotite  there  was  further  movement  which 
shattered  the  pyrrhotite  and  allowed  the  introduction  of  chal- 
copyrite  in  streaks  and  fine  veinlets  all  through  it.  Still  later, 
and  apparently  after  another  movement  calcite  came  in  and 


M: 


194 


KEMP'S  ORE  DEPOSITS. 


I 


penetrated  the  shattered  Hulphide.s  and  older  silicates.  After  the 
introduction  of  the  calcite,  hy  some  movement  fissures  notably 
horizontal  were  produced,  which  became  filled  with  glassy 
quartz,  and  which  have  yielded  the  so-called  "floors. "  Sloro 
or  less  contemporaneously  with  the  (piart/,  coarsely  cryHtMlliuo 
pyrrhotite,  chalcopyrite  and  blende  were  produced,  which  are 
in  marked  contrast  with  the  earlier  sulphides.  'I'he  oxidation 
of  the  veins  above  the  ground  water,  the  formation  of  the 
brown  hematite  outcrops  and  the  development  of  the  zone  of 
enrichment  (the  black  ores)  bring  the  process  down  to  the 
present. ' 

2.()4.();}.  Throughout  the  mountainous  region  of  western 
North  Carolina,  eastern  Tennessee  and  northern  Alabama  are 
many  other  copper  deposits  of  more  or  less  serious  imi)ortance. 
One  of  the  best  known  is  the  one  formerly  operated  at  Ore 
Knob. 

This  is  described  by  Kerr  as  a  true  fissure  vein,  extending 
2,000  feet  on  the  strike,  whicii  is  parallel  to  that  of  the  gueiss. 
but  cutting  the  dip  in  descent.  The  width  averaged  about  10 
feet.  The  gossan  extended  to  a  depth  of  oO  feet,  and  furnished 
the  usual  body  of  rich  ore  at  the  contact  with  the  sulphides. 
The  mine  has  not  been  ojierated  for  some  years.^ 

'  Trans.  Aiiiit.  J  list.  Miii.  Kikj..  is'ti). 

'■'  For  n  general  iiccoiiiit  of  l!u'  sulpliides  in  tlie  East.  ;•  «  .\.  Weudt,  "Tlie 
Pyrites  J)e|H)sits  of  tiie  Alieglianies,  "  School  of  Mines  Qnartirli/,  VII..  18.S0. 

Canada,  Gcol.  Snrvvif  of  Canada,  18(5;$.  70!).  James  Kicliardson,  Idem., 
ISiHS,  ;54_44.  R.  W.  EUs.  "  (:'o])per  in  Qiielu'C,"  fdrm.  ISiiO,  Vol.  IV., 
WK.  Kef.  "  Tiie  ^liiiinj^  Inilustries  of  Eastern  Qnrhec."  Trans.  Anicr. 
Jnst.  Min.  En<i..  XVJH.,  JUli,  IHHi).  .lolm  Hlne,  ••  Copper  Pyrites  :\Iin- 
in^  in  Quebec  in  IHitl,"  ,/()((/•//((/  (jcn'l  Miniinj  .l.s.soc.  I'ror.  Qnclnv.  II., 
liT.  ISiM.  S.  L.  Spoll'onl,  "  .Mhert  .Alines and  Capelton  Clieniical  Works," 
Idem.  214.  ('.  T.  Jackson,  ••Tlie(ireat  Cop])er  lie;irin.u:  Helt  of  ('nnada," 
Proc.  Host.  Soe.  Xaf.  Ilisf..  IX.,  'J(l'.'.  XSiVl.  Copper  jirospects  have  received 
attention  in  sonthwesteru  New  Brunswick,  on  Adams,  Campohello,  and 
other  islands.  See  Bailey  and  Matthew,  Geol.  of  Canada,  1S70-71.  p.  V-l. 
"  On  Notre  Dame  I5ay,  Newfoundland,"  1\I.  E  Wadsworth,  Amer.  Join: 
S'ci.,iii.,  XXVIll.,  '2S,  KK'. 

Maine.— "Bine  IJill  District",  Emj.  and  Min.  -lonr..  August  28,  1S80,  p. 
140.  F.  li.  Bartlett,  ".Mines  of  Maine."  in  Mines.  Miners  and  Mining 
Interr.sts  of  the  Cniled  States.  Pldladelphia,  18S3,  138.  J.  I).  Whitney. 
Metatlie  Weallli  of  tin'  Cnited  St((tes.  :\Vi. 

Nkw  HAMrsillUK.— C.  II.  Hitclic()(dv,  (1<dI.  of  .V.  //..  III..  I'art  III..  ]>  IT. 

Veu.MuNT.  —  "Eli/abeih  Copper, .Mines,"  En;/,  and  .Min.  .lonr..  Xoveiiilier 


•Tlie 

1SH6. 

iliin., 
IV., 

.1  )/((')•. 
Min- 

rr,  U., 

laila, 
•I'ived 
uikI 

p.  t:i. 

Joiir. 


,,  47. 
•eiiilier 


"^ 


2.C 

are  k 
place 


m.  : 

K(K;hr 
297.  ] 
XXI,, 

JlilU'S 

I  leposi 
.S.S.  J. 
Trails. 
posits 

INSl. 

Mounti 
Coiintj 

SUM,  "( 
.1///-.     I 

FiiiKjiii 
A  It  h  111' 

piT  .Mil 
II,  18,  : 
Coiicen 
NortliC 
"Diicki 

MK>.  :>: 
VII,,  n 

merit  o 
XXV,,  1 

a  111!  Soi 
KleiiiscI 
Vol.  111. 
Knol)  C( 

in.,  m 

Eng.  uiti 
•>n  the  ] 
TnoiiK'v, 
(Ten  11.) 
"ThePy 
Vfl.,  188 
\\'liitne,v 
''"HI  posit 
'I'enn.,   A 


copptm. 


]05 


'^.04.04.  Example  l(i/>.  Speuceville,  Cul.  Copper  ores 
are  known  and  have  been  more  or  lews  worked  in  a  nimiber  of 
places  along  the  western  SierraH,  of  wliich  Speuceville,  Nevada 

t),  iHSrt,  p.  387;  "Tlie  Pyrrhotite  of  the  Ely  Jliiie,"  Idem,  \\m\,  10,  1886. 
2(;;).  F.  M.  F.  Caziii.  Tram.  Amev.  Iimt.  Min.  Eixj.,  XXIII.,  ((04,  18«4.  H. 
Kdcluiike,  "Die  Vennoiil  I\ii|if('r  (inihe,"  liiv<j  ii.  lli'iftrii.  iicit.,  181)8, 
•Jl)7.  Kitihanlsoii,  "  tJoppcr  Ore  of  Stalloid,  Vt,  "  Aiiicr.  .lour.  Sci..  i., 
XXI,  ;{H:{.  II.  S.  Wheeler,  "  Chopper  Deiiosits  of  Vennont"  School  of 
.l//ms'  (Ji((trf<'rl!t.  IV.,  'iW).     Kec. 

I'i'NNSYLVAM.v.— Makyi.and,  AM)  Vu{(i IMA .— J.  F.  Bailey.  "Copper 
|)('|)>)sits  of  Adams  County,  Pa.,"  Eiuj.  antl  Miii.  Joiiv.,  Fehnuiry  17,  IHsy, 
HS.  J.  F.  Plniidy.  "Lake  Su|MMior  Copper  K'oeks  in  Pennsylvania," 
TniiiK.Ainc)'.  Jiisl.  Miii.  Kikj..  VII.,  'A'-M.  P.  Fiazer,  "Some  Copper  De- 
(irisits  of  Carroll  County,  Md.,  '  Tridix.  Anwr.  LiNt.  Miii.  Emj.,  IX.,  'i',\. 
issi.  "Hypothesis  of  the  Structure  of  the  Copper  Pelt  of  the  South 
Mountain,  hkm,  XII.,  H'2,  1884  "  (Jeoloj;y  and  Copj)er  Deposits  of  Adiinis 
(.'(.unty.  Pa.,"  Einj.  and  Min.  Jour.,  XXXV..  II'.',  ls.s;i.  f.  H.  Hender- 
son. •t'o])per  Deposits  of  the  South  Mountain,  Pa.."  Troiin.  Ainei:  Inat. 
Mill.  Eiiij.,  XII.,  8.'),  1884.  C.  T.  Jack.son,  "  Coi)per  Mine,  Elk  Pun, 
J'auiiiiier  County,  Va,"  Prov.  Host.  Soc.  Not.  Hist.,  VI.,  18;J,  1857. 
Artlun-  Keith,  Harjier's  Ferry  Folio,   U.  8.  Oeological  Siirvcif. 

Ndiaii  Cauomna,  Ten.nksskk,  and  .\i..\bama.—"  The  Stone  Hill  Cop- 
pi  r  Mine  and  Works,  Cielairne,  Wn.."  Eiitf.  ami  Miii.  Jour.,  Aujjrust  4. 
II,  18,  1877,  i)p  81)  and  followin;^.  W.  P.  Blake,  "  Notes  and  Recolleetions 
Concerning  the  Mineral  Kesources  of  Northern  (ieorj^ia  an<l  Western 
North  Carohna."  Trans.  Aiiiir.  ///.s7.  .1//)).  Eikj.,  XXV.,  7!K(.  W.  B.  Brewer. 
■  Dncktown  Collier  JlimiiK  District,"  i?Hf/.  aiul  Min.  Jour.,  Jlan^h  33, 
IH!),"),  271.  "Copi)er  Mining  in  Alabama,"  Proc.  Ala.  Ind.  and  Sci.  Soc, 
VII.,  13,  1807.  Carl  Ilenrich,  "The  Duektowu  Deposits  and  the  Treat- 
ment of  the  Ducktown  Coj^jer  Ores.  '  Trans  ^[nnr.  Just.  Min.  Kinj., 
XXV.,  173,  18!ir).  Kee.  J.  F.  Kemi),  "The  Order  of  Formation  of  the 
.Mincriils  in  the  Ducktown  Veins."  Idem.  18!»!).  T.  S.  Uxrnt.  "Ore  Knob 
anil  Some  Related  Deposits,"  Trans.  Aiiier.  Inst.  Min.  Eng.,  II.,  135. 
Kleiusehmidt  (on  Virginia,  Tennessee,  and  North  Carolina),  Ganfistadien, 
Vol.  III.,  p.  25().  (A  good,  short,  but  old  account.)  E.  E.  Olcott,  "Ore 
Knob  Copper  Mini!  and  Peductiou  Works,"  Trans.  Amer.  Inst.  Min.  Eiuj., 
III.,  3111.  Kec.  W.  B.  Phillips,  "Copper  Deposits  of  North  Carolina," 
Eiig.  and  Min.  Jour.,  Ajn-il  1,  1899,383.  Trijjple  and  Credner,  "Report 
i>n  the  Ducktown  Region  to  the  American  Biu-eau  of  ]\Iiiu^s,"  18(iG.  M. 
Tuoiuey,  "A  Brief  Note  of  Some  Facts  Connected  with  the  Ducktown 
(Teuu.)  Copper  Mines,"  Amer.  Jour.  Sci..,  II.,  19,  181.  A.  F.  Wendt, 
"The  Pyrites  Deposits  of  the  Alleghanies,"  Seliool  of  Mines  Quarterly,  Vol. 
VII.,  lss(i;  Eng.  and  Min.  Jour.,  July  10  and  following,  188(5.  J.  D. 
Whitney,  "Remarks  on  the  Changes  that  Take  Place  in  the  Structure  and 
'iiniijosition  of  Jlineral  Veins,"  etc.,  with  especial  reference  to  Ducktown, 
'I'enn.,   Amer.  Jour.  Sci.,  ii.,  XX.,  53. 


190 


KILMl'S  OliE  DEPOSITS. 


m 


County,  Copperopolis  and  Campo  Seoo,  CalaveraH  County,  and 
Newton,  Amador  County,  are  the  most  important.  There  aio 
some  difTerenccH  m  the  geological  rolatiouH  of  these  Hevcral 
deposits,  but  they  are  alike  in  being  associated  with  igneous 
rocks.  At  Spenceville  the  ores  occur  in  veins  along  the  contact 
of  diabase  and  grano-diorite.'  In  Amador  County  two  belts 
of  ore  have  been  developed  in  amphibole  schists.  There  are 
mines  at  lone  and  Caledonia,  and  other  openings  extend  in  a 
sontlicasterly  line  to  Copju'ropolis  in  Calaveras  Count  'ho 

amphibolite  schist  is  a  metam(jrj)hosed  diabase  or  por^  yrite. 
In  some  of  the  mines  (jnartz  porphyrite  is  associated  with  tlie 
veins."  Other  copj)er  deposits  have  been  discovered  in  the  areas 
covered  by  the  Sonora  and  Placerville  folios."'  They  occur  in 
porphyrites,  amphibole-schists,  serpentine,  and  in  contact  zones 
next  the  intrusions  of  grauo-diorite. 

Far  to  the  north  of  all  the  deposits  cited  above  a  very  extensive 
body  of  sulphides  has  been  opened  at  Iron  Mountain,  and  bids 
fair  to  afford  high-grade  ore  for  this  type.  The  wall  rock  is 
described  as  a  highly  siliceous  porphyry.* 

The  California  co{»per  ores  have  been  treated  by  wet  methods 
to  a  large  extent,  and  have  contributed  considerable  fuuiiiits 
to  the  total  output  of  the  country. 

Note.     For  Example  Kic,  see  under  Nickel.     Sor  tho 

California  mines  appear  to  be  closely  related  to  10c. 

•^.04.05,  Example  17.  Butte,  Mont.  Veins  in  fissures  in 
granite,  which  have  involved  but  slight  dislocation,  and  which 
have  been  enlarged  by  replacement  of  the  walls  with  ore.  'Ihe 
vein  filling  is  -^al'ceous,  and  the  metallic  ores  in  the  deposits 

'  Ijiiu]fi;ren  and  Turner,  Sinartsville  Folio,  U.  S.  Geological  Snirvii 
See  also  J.  E.  Ellis.  '-On  the  Spenceville  Jlines,"  Mineral  Ih'soinna  i4 
the  U.  S.;  U.  S.  (Itol.  Snrvvji.  1SS4,  840.  H.  (4.  Hanks.  Rept.  of  Calijornio 
State  MiaerahHjiat,  1HS4,  lol.     J.  B.  Hobson,  Idem,  for  1890,  km. 

''  IT.  W.  Turner.  Jackson  Folio.  U.  S.  Gcol.  Sioren.  II.  (i.  IlMnks. 
"On  Calaveras  County  Mines,"  Fourth  Ann.  AVjj.  C'al.  State  Mineraloijift. 
48,  1890.  \Vm.  Irelan,  Idem,  1888,  150-153;  "On  the  Newton  Mine-*. 
Amador  Co.." /f/(';u.,  p.  100. 

'  Turner  and  Ransonie,  Sonora  Folio;  Lindgreu  and  Turner,  Placerville 
Folio,  U.  S.  Oeol.  Snrvey. 

*  H.  Lang,  "Iron  ^Mountain  Mine,  Sliasta  Co.,"  Eng.  and  Min.  Jour.- 
April  15,  ^2.  and  ]May  i;3,  1899.  The  paper  also  mentions  other  coi'l"^'' 
mines  in  this  regi<jn. 


COPPKR. 


197 


]iriKluctive  of  copper  are  cimlcopyrite,  pyrite,  bi)ruite,  olmlco- 
cite,  I'lifirgite,  and  rarely  cov»)llito  aini  toiinautite.  'J'lio  copper 
(iri'M  contain  much  nil v(>r  and  sonio  g(»M,  l)nt  tliere  is  a  fairly 
distinct  HerieH  of  Hilvcr-boaring  veins,  wliicli  contain  practically 
no  copper,  and  which  have  nianj^aneao  minerals  that  fail  in  the 
copper  veins.  And  yet  along  the  borders  of  the  two  areas 
tlime  are  veins  which  are  somewhat  transitional  between  the 
two  varieties. 

Tiie  geological  formations  at  Butte  are  illustrated  on  the 
accompanying  map.  Figs.  .')S  and  ."i'.i,  which  are  bastul  upon  the 
map  of  the  areal  geolog}-  in  tlie  Butte  Sp'ocial  Folio  of  the  U,  S. 
Oi'ohxjical  Siirveij.  The  colors  of  the  original  are  reproduced 
iu  lines,  and  some  small  dt'tails  have  necessarily  been  omitted 
ou  account  of  the  reduction  in  Hize,  and  the  confusion  of  signs 
without  colors.  The  only  omisi^ions,  however,  area  few  small 
areas  of  the  Bluebird  granite,  and  of  the  riiyolite.  In  the 
ordinal  map  the  areal  geology  is  by  W.  H.  Weed,  and  the  veins 
and  n;iniug  geology  have  been  mapped  by  S.  F.  Enunons  ami 
G.  W.  Tower.  The  work  was  ditKcult  and  complicated,  but  it 
lias  been  admirabl}'  done. 

The  Butte  mining  district  lies  on  the  southern  and  eastern 
slopes  of  a  hillside  or  upland  that  rises  from  the  valley  of  Sil- 
ver Bow  Creek.  The  hillside  is  cut  [)y  several  minor  north  and 
south  gulches,  and  is  bounded  oi  the  south  and  east  by  the 
valley  of  the  creek,  which  makes  a  rescentic  sweep  around  it. 
Just  to  the  west  of  the  town  rises  a  sharp  cone  of  rhyolite, 
which  is  shown  in  Fig,  lio,  and  which  gave  the  camp  its  name 
ill  the  early  days.  In  the  distance,  on  all  sides,  high  mountain- 
ous ridges  rise  like  walls  as  is  shown  iu  Figs.  <il  and  i'>-i.  The 
oldest  rock  of  the  district,  and  the  one  which  covers  the  greatest 
area,  is  a  basic  granite.  Chemical  analyses  prepared  by  the  U. 
^>.  Geological  Survey  have  proved  it  to  be  exceptionally  low  in 
silica  for  a  granite,  and  to  he  (piito  uniform.  SiOa  ri;{.s,S-(i4.;i4, 
AW,,  1.0. 38-1.5.84,  FeO,  FeJ\  4.0-4.:,  CaO,  ^^^)7-^.•^,  MgO, 
2.()8-2.-^:},  KaO,  4.0-4.'2:5,  Na.O,  •2.r4-t>.8l.  This  rock  is  called 
the  l>utte  granite.  It  is  the  wall-rock  of  all  the  copper  veins 
and  of  most  of  the  silver  ores.  It  lies  east,  north  and  south  of 
the  Big  Butte.  The  intrusion  of  the  Butte  granite  was  followed, 
presumably  after  a  short  interval,  by  a  white,  acidic  granite 
known  as  the  Bluebird.     An  interesting  contact  of  the  two  is 


198 


KEMP'S  ORE  DEPOSITS. 


♦ 


liTTTK  nilANITE 


BLrEniHl)  OUANITE  QUARTZ  POKFHVRY 


WMM     m 


ii!iini:ii:,!,iii 


HHYOLITK 


Fig.  58. — Geological  map  of  the  Western,  half  of  Butte  District,  Montana,  re- 

produced  in  line-work  front  the  colored  map  of  the  Butte  Special 

Folio,  U.  S.  Geological  Survey. 


COPPER. 


199 


:l 


^ ^-jy;,- 


-c" 


ixony 


'  V. 


\^l 


,ll.l 


FlQ.  59. — Oeolofjical  map,  Knxtfrn  half,  Butte  District,  Montana. 

See  Fig.  58. 


:!;l 


200 


KEMP-S  ORE  DErOSJTS. 


m 


III 


shown  in  Fig.  'Jo.  It  is  supposed  to  have  separated  from  the 
same  magma  that  allforded  the  Butte  grauite  and  to  have  pene- 
trated fissures  in  the  latter  while  it  was  probably  still  hot,  as  it 
is  now  found  in  all  manner  of  small  veins  and  masses,  which  do 
not  show  any  effects  of  (juick  chilling  along  the  contacts.  The 
Bluebird  granite  is  most  extensivel}'  developed  in  the  western 
part  of  the  district,  but  it  appears  on  all  sides  of  the  Big  Butte 
in  small  patches.  The  next  rock  in  time  is  (juartz-porphyry, 
which  is  found  on  the  slopes  west  of  Butte  City,  and  between  it 
and  Meaderville.  After  the  intrusion  of  the  quartz- porphyry  the 
fracturing  occurred,  which  gave  rif^e  to  the  veins,  for  the  latter 
cut  the  (juartz-porphyry  in  a  number  of  instances.  After  the 
deposition  of  the  ore,  the  great  intrusion  and  eruption  of  the 
rhyolite  took  place,  which  now  appears  as  many  dikes  cutting 
the  veins,  as  a  great  sheet,  and  as  some  masses  of  fragmental 
ejectments.  While  the  rhyolite  was  in  eruption  a  lake  existed 
in  the  western  part  of  the  district,  and  in  it  werw  deijosited 
great  quantities  of  rhyolitic  volcanic  dust,  which  now  chieliy 
constitutes  the  Lake  Beds  of  the  map.  These  beds  have  been 
traced  to  the  south  and  west  beyond  the  limits  of  the  map,  and 
have  been  found  to  contain  Miocene  fossils. 

Outside  the  area  of  the  map  the  Butte  granite  is  known  to 
penetrate  Carboniferous  strata,  and  it  is  not  certai.a  that  it  may 
not  have  followed  Laramie  l)eds.  It  is,  certainly  post-Carboni- 
ferous, and  it  may  be  post-L;iramie.  Tlie  veins  must,  there- 
fore, have  been  filled  in  the  interval  between  the  close  of 
the  Carboniferous  and  the  Miocene,  and  perhaps  are  post-Cre- 
taneous.  The  recent  gravels  constitute  the  formation  called 
alluvium.  They  are  extensive  in  the  valleys  of  the  creeks  and 
at  times  quite  deep. 

Butte  was  first  developed  as  a  placer  camp  as  early  as  lS>'i, 
when,  according  to  Enmions  and  Tower,  the  gravels  of  ]\lis- 
soula  Gulch  were  washed.  As  the  (juartz  ledges  constituting 
the  veins  still  project  in  many  instances,  like  great  walls,  it  i.s 
not  surprising  that  they  were  early  noted  and  located.  Figures 
illustrative  of  them  and  of  the  excessive  weathering  of  the  Butte 
granite  will  be  found  under  silver  in  Montana,  Chapter  X.  Small 
success  attended  the  first  efforts  jf  the  deep  miners  until  rid) 
silver  ore  was  found  in  the  Travona  in  isld.  The  copper  dis- 
coveries came  three  or  four  years  later,  because  the  copper  liad 


Fiti.  00.  —  Vicir  of  the  Biij  Ihittc.   Butte  City.    M(»it.,  looking  northicest 

across  Missonld  (7nlc]t.     From  n  photogntph  by 

J.  F.  Koiip,  Jinio,  18',»6. 


CS    Hiul 
AS   1^^'i, 

of  ^lis- 
;itutiiig 
Irt,  it  i« 

le  Bntte 
.  s;niall 
itil  i'i''l> 


)jiei'  .'li 


1.1 


Fio.  61. — View  of  the  Anaconda  Mine  {with  the  nine  stacks),  Butte,  Mont. 
From  a  photograph  by  Alexander  Brown,  E.  31.,  1896. 


m- 


•-, 


*>  2 


5   -^^ 


fi:    I  'J 


in 


^  .;  5> 


5   c  -^ 


i    v   5 


quit 

the 

aroii 

beei 

bod  i 

ored 

faik 

and 

l)or<  I 

rich 


COPPER. 


201 


"^1 


Hi 


1  r* 


m 


w  W       '^^ 


C5  .=  I 

5  c  4 


5-  ■-  ? 


•^i 


been  leached  out  of  the  portiou  of  the  vein  above  the  ground- 
water, leaving  the  silver  behind.  When,  however,  the  huge 
masses  of  chalcocite  and  bornite  were  met  in  the  zone  of 
enrichment,  the  co{)per  production  became  established. 

Study  of  the  map  will  show  tiiat,  although  so  numerous,  the 
veins  all  run  in  an  east  and  west  direction,  that  they  are  closely 
parallel,  and  that  at  the  most  they  vary  not  more  than  45  degrees 
north  or  south  of  this  line.  They  dip  at  high  angles,  being 
almost  always  overOO  degrees.  The  dip  is  to  the  south,  except 
in  the  northern  edge  of  the  district,  where  the  inclination  is 
prevailingly  to  the  north. 

Small  offsetting  veins  often  connect  the  larger  ones  and  even 
nm  into  the  wall  rock  as  blind  veins.  Vein  lets  of  all  sizes  can 
be  observed  on  the  dumps.  The  ore  varies  from  five  or  six  feet 
tC'  as  much  as  100  feet  across  in  the  extreme  cases.  The  origi- 
nal fissures  do  not  appear  to  have  involved  much  empty  space, 
however,  and  the  deposition  has  been  in  the  nature  of  a  replace- 
ment of  the  walls,  and  the  process  may,  indeed,  have  extended 
from  fissure  to  fissure,  removing  the  intervening,  rarely  brec- 
ciated  country  rock.  The  ore  habitually  fades  out  into  the  coun- 
try rock  at  least  on  one  side,  and  as  a  rule  all  the  companies 
liave  to  concentrr.te  the  run  of  the  mines.  Since  the  completion  of 
ore  deposition,  there  has  been  extensive  later  dislocation,  which 
is  shown  by  brecciated  faults,  which  ma}*  follow  along  the 
veins,  or  may  cross  and  fault  them.  They  are  now  filled  with 
material  more  or  less  fully  kaolinized  and  are  practically  bar- 
ren, except  where  they  have  dragged  vein  matter  into  their 
snbstance  during  faulting,  or  have  been  impregnated  during 
the  alteration  of  the  older  veins. 

■.'.(I4.0ii.  The  ground  distinctively'  productive  of  copper  is 
•luite  sharpl}'  marked  off  from  that  yielding  silver  alone  (all 
the  copper  ores  have  silver)  and  a  wavy  line  has  been  run 
around  the  former  on  the  map.  The  copper  area  seems  to  have 
been  the  center  of  the  mineralization,  and  in  it  the  largest  ore- 
bodies  are  found.  Copper  and  silver  solutions  especially  fav- 
ored tliis  portion,  and  on  its  edges  the  copper  gradually 
tailed,  while  with  the  silver  came  \wc^">  or  less  zinc  and  lead, 
■•md  increasing  manganese.  The  Gagnon  mine  that  is  on  the 
l)ord^>r  is  transitional,  as  the  ore  yields  copper,  but  is  also  very 
rich  in  silver,  and  contains  considerable   blende  and  galena. 


*^02 


KEMP'S  ORE  DEPOSITS. 


The  mineralogy  of  the  silver  series  is  more  fully  described 
under  Silver,  Chapter  X.  The  c6j)per  ores  contain  a  small  l)ut 
constant  value  in  gold,  and  there  is  some  reason  for  thinking 
that  the  gold  occurs  as  a  telluride.  While  tellurium  is  present 
in  very  small  amounts,  it  can  be  saved  by  the  refiners  and  sup- 
plied in  (quantities  that  are,  for  this  rare  element,  enormous. 

The  oxidization  or  alteration  of  the  veins  above  the  ground- 
water presents  points  of  interest.  As  the  wall-rock  is  granite, 
carbonates  and  oxides  of  cop})er  are  poorly  developed  and  the 
oxidized  ores  are  in  contrast  with  those  in  limestones  and 
schists.  Chalcocite,  bornite  and  covellite  are  the  principal 
secondary  copper  minerals  that  have  resulted,  and  the  last  named 
lies  chietly  along  fractures.  Thechalcocite  and  bornite  are  not, 
however,  limited  to  the  present  water-level,  but  have  pene- 
trated far  below  it,  and  have  enriched  the  veins,  and  a  reasona- 
ble query  may  be  raised  as  to  whether  they  may  not  be  in  part 
original  depositions.  The  gangue  is  quartz,  in  decomposed 
country  rock.  Barite  in  honey-yellow  tabular  crystals  is  oc- 
casionally met,  but  is  only  a  curiosity.  The  outcrop  of  the 
silver  veins  is  stained  black  by  manganese  oxide. 

To  the  east  of  the  area  of  tlie  map  and  on  the  slopes  of  the  ^ 
bounding  range  of  granite  mountains,  the   veins   Outcrop  as 
ledges  of  quartz,  and  considerable  prospecting  has  b^en  (lone. 
Some  copper  ores  have  indeed  been  found,  butthedeVelopmeiits 
do  not  jet  (ISliii)  assure  profitable  mining. 

2.(»4.()r.  The  total  production  of  Butte  to  the  close  of  ISlni 
is  estimated  by  Emmons  and  Tower  to  have  been  ^;:)(K).()()(),(i(iO, 
divided  somewhat  as  follows:  Gold,  500. ()()()  ounces;  silver, 
100,000,000  ounces;  copper,  1,000,0()(),0()0  pounds.  In  lyit?,' 
accoriiing  to  The  Mineral  linhisfri/,  the  copper  produced  was 
SoT, ir)S,540  pounds,  of  which  tbe  Anaconda  Com})any  con- 
tributed KJl. 471, 1-^7.  On  the  whole,  tbe  Butte  copper  district 
is  the  most  productive  of  those  as  yet  opened  intlie  United  States.' 

'  The  best  .account  of  Butte  will  he  foutul  in  the  Ikitte  S[)ecial  Folio,  <>( 
the  U.  S.  C>riil.  Sin  rci/.  in  wliich  tlie  areal  };eolo<,'y  is  hy  \V.  U.  Weed,  iiinl 
the  mining  geology  by  S.  F.  Emmons  imd  (J.  W.  Tower.  This  reference 
has  been  es])eciiilly  drawn  upon  in  the  above  description.  "  lUilte  Copjier 
Mines,"  Eiuj.  (did.  Min.  .four.,  April  '24,  1H,%,  SiW;  .hine  19,  iss(i.  445.  1! 
G.  Brown,  "The  Ore  DeiKvsits  of  Butte  City,"  Tnnix.  Anwr.  In.st.  Min 
Eny.,  XXIV.,  Wij.  Rec.  S.  F.  Ennuons,  '-Notes  on  the  (ieology  of 
Butte,  Mont.,"  Trans.  Aiiicr.  Iii.st.  Min.  Eiig.,  XVI.,  41).     C'li.  \V.  (i l:ilf. 


k)iit'. 
Mits 


i,(i(iO, 
ilver, 


i\y 


is'.i 
^^as 

striit 
ites.' 

ilio,  of 

(I.  ami 

tt'i-t'iice 

jl'iil'l'*''" 
4.-,.  U 
\l    Mill 


?.'^ 


=   CQ 

^ 

X, 

■t^      "^ 

5> 

■K» 

■^        -w 

o 

?    z. 

^ 

^  ^ 

^ 

^  =  -Si 


CO 


irV     II 


ale, 


■9P 


• 

IK, 

iri 

^ 

.^i^H 

1 

'i^H^Rj^^^^H 

!?■' 

';l^fl^^H 

It 

COPPER. 


203 


There  are  copper  pronpects  in  northwestern  Montana  within 
the  limits  of  the  Lewis  and  Clarke  Timber  Reserve,  and  amid 
the  high  peaks  of  the  Rockies  near  the  iuternatioual  boun^'ary. 
The  general  geology  ,^  the  country  involves  Cambrian  and 
Precamhriau  (juartzites,  in  which  are  intrusions  of  igneous 
rocks,  of  the  nature  of  andesites  or  diorites.  Copper  ores  are 
found  in  association  with  the  latter.' 

2.04.08.  Exam})le  17«.  Gilpin  County,  Colorado.  Veins  of 
pyrite  and  chalcopyrite,  replacing  gneiss  (the  rock  may  be 
granite),  and  dikes  of  (iuart7,-i)orphyry,  and  felsite  along  the 
jdanes  of  joints,  whicli  cross  the  gneiss  (or  granite)  perpendic- 
ularly to  the  laminations.  The  veins  are  highly  auriferous, 
and  are  worked  primarily  for  gold,  the  cojjper  being  produced 
as  a  by-product.  The  concentrates  from  the  stamps  are  after- 
ward treated  for  coi)]ier.  The  veins  occupy  an  area  of  only 
about  a  mile  and  a  half  in  diameter,  centering  about  Central 
City.  They  show  little  indication  of  having  tilled  a  fissure,  as 
usually  understood,  but  follow  the  cleavage  joints  of  the  gneiss, 
and  replace  the  countrj'  rock  on  each  side  of  them.  The  joints 
also  cross  the  porphyry'  dikes,  and  the  veins  are  often  in  the 
latter  rock.  They  are  closely  related  in  structure  and  origin 
to  the  galena  veins  of  the  neighboring  Clear  Creek  County, 
Avhich  are  referred  to  imder  "Silver,"  but  the  contrast  in  min- 
eral contents  between  the  two  is  very  marked.     They  were  the 


" Tlie  Concentration  of  Ores  in  the  Bntte  District,  ]\Iont.,  Idem.,  XXVT., 
.V.l'.l,  UOS.  Eicliard  Peurce,  "The  Association  of  Minerals  in  tlie  liagnon 
Vein,  Butte Cit}'.  Mont.,  Tiann.  Amcr.  Innt.  Miii.  Eiig.,  XVI.,  62;  "Ontlie 
Occurrence  of  (ioslarite  in  tlie  (Jagnon  Mine.  Rutte  City,  '"  Pi-oc.  Colo. 
Sri.  Soc,  Vol.  II.,  Parti.,  p.  Vi.  E.  I).  Peters,  Mineral  ResoKrcea  of  Ihe 
r.  S.,  18H3-84,  p.  :iT4.  .\.  Williams  and  E.  D.  Peters,  "On  Butte,  Mont." 
'■:ii<l-  (iiiil  Mill.  Join-..  March  2:5.  188.").  j).  208.     O.  voni  Path.  "Ueber  ilas 

;iii,t:;revier  von  Butte,  Mont.,"  ?^\'insJalirbiieli.  188,"),  I.,  MS. 

Important  annual  reviews  are  also  published  in  the  Ann.  Reps,  of  Ihe 
I)  nrfor  of  the  U.  S.  Geol.  Snrren  ami  in  The  Mineral  Jnduxtrii.  The  lat- 
ter is  especially  valuable  in  cotuiection  with  the  teclinok)gy  and  mining. 
<ienenil  papers  on  co]iper  ])rodiiction  likewise  touch  on  Butte,  such  as 
.IiiiiK's  Douglass.  "The  C'oi)per  Resources  of  the  United  Htate.s,"  Trans. 
Aiiiir.  Inst.  Mill.  Eiig.,  XIX..  0T8.  Some  additional  literatiu'e  is  given 
umlcr  "Silver,"  2.10.(t!). 

'  R.  C.  Chapman,  "The  Geological  Structure  of  the  Rooky  Mountains, 
within  the  Lewis  and  Clarke  Timber  Reserve,"  Trans.  Ainer.  Inst.  Min. 
Emj.,  February,  1899. 


204 


KKMP'S  OHK  DEPOSITS. 


\ '« ; 


basis  of  the  first  extensive  deep  mining  in  Colorado,  and  worn 
located  through  the  placer  deposits  in  the  neighboring  gulches.' 

2.04.00.  Exam})ie  17/>.  Llano  County,  Texas.  Impregna- 
tions in  granite,  and  veins  with  quartz  gangue  in  granite,  rany- 
ing  carbonates  above,  butsulphurets  and  tetrahedrite  with  some 
gold  and  silver  below.  Contact  deposits  between  slates  and 
granite  are  also  known.  It  is  not  demonstrated  as  yet  whether 
the  ores  are  to  be  actually  productive.^ 

2.04.10.  Example  IS.  Keweenaw  Point,  Michigan.  Native 
copper,  with  some  silver,  in  both  seilimentary  and  iuterstrati- 


FiG.  04.- 


-Cronx  K'Ctiiiii  iij't/ic  liiihtiiU  iiiiiH's,  ('entrnl  ('Uij,  'Olo. 
F.  M.  Kiidlii'li,  Ilainhn'x  Surrey,  IHTIi,  p.  2H«. 


After 


fied  igneous  rocks  of  the  Keweenawan  system.  The  metal  oc- 
curs as  a  cement  binding  together  and  replacing  the  pebbles  of 
a  conglomerate;  or  filling  the  amygdules  in  the  upper  por- 
tions of  the  iuterbeddeil  sheets  of  massive  rocks;  or  as  ii regular 
masses,  sometimes  of  enormous  size,  in  vtius,  with  a  gaugne 
of  calcite,  epidote,  and  various  zeolites;  or  in  irregular  masses 
along  the  contacts  between  the  sedimentary  and  igneous  rocks. 
(For  the  general  geography  see  Fig.  ^4,  p.  12G.) 
2.04.11.     The    rocks  of   the  Keweenawan   system  are  most 

'  S.  F.  Enmions,  Tenth  Censnn,  Vol.  XIII. ,  p.  08.  Tlie  veins  are  de- 
scribed as  cited  above.  J.  D.  Hague,  Fortieth  Paratld  Siirwif,  III.,  p.  4!l;). 
Tbe  veins  are  oalletl  fissure  veins  by  Mr.  Hague.  A.  Lakes,  Ana.  Rep. 
Colo.  State  School  of  Mines,  1887,  p.  103.  A.  W.  Rogens,  "Tlie  Mines  and 
Mills  of  Gilpin  County,  Colorado,"  Trans.  Anier.  Tn.^t.  Min.  Eng.,  II., 'J!>. 
Further  references  will  be  found  under  "Silver  and  Clold  in  Colorado." 

"  T.  B.  Coinstock,  First  Ann.  Rep.  Texas  Ocol.  Survey,  1889,  p.  334.  W. 
F.  Cununins,  Idem,  190.  W.  H.  Streeruvvitz.  in  Mineral  Resources  of  the 
U.  S.,  1884,  p.  343. 


coprh'ii. 


205 


Htron^ly  deVt'loped  on  the  .soutli  nliore  of  Lake  Superior,  espe- 
cially in  Keweenaw  Point,  whicii  jntH  out  uortheaHterly,  cut- 
ting the  lake  into  two  nearly  ecpuil  portions.  They  extend  some 
ilistance  east  and  west,  and  are  also  known  on  the  north  shore. 
They  consist  of  sandstone  and  thin  hcds  of  conglomerate,  inter- 
stratified  with  sheets  of  diahase,  hoth  conipact  and  amygdaloi- 
dal,  and  of  melaphyre.  They  are  succeede«l  on  the  east  by  the 
Eastern  Sandstone,  which  on  the  south  shore  is  thought  by 
Irving,  Chamberlin  and  others  in  some  })lace8  to  abut  uncon- 
formal)ly  against  them,  and  in  others  to  pass  under  them  from 
an  overthrust  fault.  Wadsworth,  however,  coijsiders  that  the 
Eastern  Sandstone  passes  conformably  beneath  the  Keweena- 
wan,  and  that  it  is  older. 

The  Eastern  Sandstone  forms  a  comparatively  low,  flat  bench 
some  miles  across,  between  the  lake  and  the  ridge  of  the  Ke- 
weenawan,  whose  rocks  rise  (juite  abruptly  in  a  marked  escarp- 
ment. The  several  streams  that  fall  over  this  scarp  in  cas- 
cades have  served  by  their  erosion  to  expose  the  contacts. 
The  best  known  are  the  Hungarian  and  Douglas  Houghton 
Rivers.  On  the  west  or  northwest  side  the  escarpment  is 
much  less  pronounced  and  the  contact  is  less  well  shown  and 
has  not  been  so  sharply  located.  The  sandstone  is  called  the 
Western  Sandstone.  It  is  now  pretty  well  shown  that  the 
Eastern  Sandstone  is  a  close  eJiuivalent  to  the  Potsdam,  for 
though  itself  lacking  in  fossils,  it  is  known  to  pass  conformably 
beneath  fosailiferous  Lower  Silurian  limestone  near  L'Anse. 

On  Keweenaw  Point  the  beds  dip  northwesterly  and  pass 
under  Lake  Superior  to  reappear  with  a  southeasterly  dip  on 
Isle  Royale  and  the  Canadian  shore.  Western  Lake  Superior 
occupies  this  synclinal  trough.  In  Keweenaw  Point  the  dip  is 
greatest  on  the  southvest,  being  about  00°  at  Hancock.  To 
the  northeast  it  gradually  flattens  to  150°  or  less  on  the  lake 
shore.  (For  the  general  geology  of  the  neighboring  region  see 
under  Example  9.) 

It  is  interesting  to  note  that  the  early  investigators  of  the 
geology  of  this  country  drew  a  parallel  between  the  sandstones 
and  traps  of  Lake  Superior  and  the  similar  Triassic  deposits  of 
the  Atlantic  coast  (see  Example '^1),  even  going  so  far  as  to 
regard  the  former  as  the  western  equivalent  of  the  latter.^ 

'  C.  T.  Jackson,  Amer.  Jour.  Sci,  i.,  XLIX.,  1845,  pp.  81-93. 


i06 


h'h'MP'S  OnE  DEPOSn'S. 


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207 


There  are  three  prinoipal  uiiuing  (lintricts — the  Keweenaw 
Point,  on  the  end  of  the  Point;  the  Portage  Lake,  in  the  middle; 
and  the  Ontonagon,  at  the  western  hase.  Mines  have  also  heeu 
worked  on  Isle  Koyale,  and  cojjjht  is  found  in  small  amounts  on 


XXXV  xxxiv  xxxiu  xxxn 

Fui.  (Ki. — Map  of  the  Portage  Lake  IHntriet,  Keweenaw  Point,  Mich.     Adap- 
ted from  a  map  in  the  catalogue  of  the  Michigan  College  of  Mincn. 

tbe  north  shore.     The  Portage  Lake  district  is  now  the  ])rinei- 

pal  and  almost  the  only  producer.     In  the  first-named  district 

'st  of  the  mines  are  on  original  fissures,  which  have  later 


208 


KEMP'S  QUE  DEPOSITS. 


becoxue  much  enlarged  by  the  alteration  of  the  walls.  They 
are  usually  from  one  to  three  feet  broad,  but  may  reach  10,  ^0, 
and  oO  feet,  this  last  in  the  more  loosely  textured  rocks.  These 
expansions  are  also  richer  in  copper.  The  veins  stand  nearly 
vertical,  and  cross  the  beds  at  right  angles.  They  were  the 
earliest  discovered,  and  the  first  to  be  extensively'  worked. 
The  metallic  masses,  both  large  and  small,  occur  distributed 
through  the  gangue.  The  best-known  mines  of  the  district  are 
the  Central,  Cliff,  Phoenix  and  Copper  Falls.  AH  have  been 
reeentl}'  closed  except  the  Central,  which,  after  temporary  sus- 
pension in  181U,  resumed  operations  in  18!h;.  A  conglomerate 
a{)peared  to  cut  off  the  vein,  although  probald}'  a  fault  and  move- 
ment parallel  with  the  dip  occasioned  the  displacement.  With 
favorable  markets  several  other  vein  mines  may  be  intermit- 
tentlj'  worked.  The  vein  mines  have  been  the  great  source  of 
fine  minerals  in  the  past,  the  Phoenix  being  well  known  for 
its  zeolites. 

2.0-i.r^.     In  the  Portage  Lake  district  the  mines  are  either  in 
conglomerate  (Calumet  and  Hecla,  Tamarack,  Peninsula,  etc.) 
or  in  amj'gdaloidal,  strongl}'  altered  diabase,  certain  very  sco- 
riaceous    sheets   of   which   are   known   as   ash-beds    (Quiiicj', 
Franklin,  Atlantic,  etc.).    In  the  conglomerates  the  copper  has 
replaced  the  finer  fragments,  so  as  to  appear  like  a  cement,  aud 
often  the  boulders  themselves,  or  particular  minerals  in  them, 
are  permeated  with  copper.       The  rich  portions  are  of  limited 
extent  along  the  strike  as  they  give  way  to  barren  rock,  after 
a  stretch  it  may  be  of  several  thous.mds   of  feet,  and  they  go 
down  as  great  chutes  somewhat  diagonally  on  the  dip  to  very 
great  depths.     The  Tamarack  workings,  below  the  Calumet 
and  Hacla,  have  been  pushed  on   the  bed  ni^arl}'  a  mile  below 
the  outcrop,  and  show  no  diminution   or  essential  change  in 
the  copper  rock.     Three  copper- bearing   conglomerates  have 
been  identified,  the  Calumet  and  Hecla,  the  Albany  and  Ko-:- 
toii  (also  called  the   Peninsula)  and  the  Ailouez.     The  first  is 
much  the  richest,  but  has  not  been  found   productive  at  auy 
other  point  on  the  strike  than  in  the  great  mine  which  gives  it 
its  name.     The  amygdaloids  have  copper  in  their  small  cavi- 
ties, but  in  the  open  or  shattered   rock  it  fills  all   manner  of 
irregular  spaces,  often  in  fragments  of  great  size.     It  is  asso- 
ciated  with  calcite,  zeolites,  datolite,  epidote,  and   a  chloritic 


COPPER. 


209 


mineral,  or  "green  earth"  containing  Fe^jO;,,  Tlie  distribution 
of  the  C()i)per  in  the  amygdaloidal  sheets  is  much  tlie  same  as 
in  the  conglomerates.  It  is  limited  along  the  strike,  and  goes 
down  at  a  slight  diagonal  in  great  chutes  whose  ends  have 
never  yet  lieen  reached.  This  arrangement  must  have  an 
important  bearing  on  the  method  of  origin. 

2.04.  i;5.  In  the  Ontonagon  district  the  copper  follows 
planes  approximately  parallel  to  the  bedding  of  the  sandstones 
and  igneous  rocks,  and  in  one  case  at  least  (the  National  mine) 
along  the  contact  hetween  the  two.  The  copper  is  (juite  irregu- 
lar in  its  distribution,  but  has  the  same  associates  that  are 
mentioned  above. 

On  the  Oriqin  of  the  Copper. — The  original  source  of  the  cop- 
per was  thought  by  the  earlier  investigators  to  be  in  the  erup- 
tive rocks  themselves,  and  that  with  them  it  had  come  in  some 
foim  to  the  surface,  and  had  been  subseijuently  concentrated  in 
thecavitips.  Pumpelly  has  referred  it  to  copper  sulphides  dis- 
tributed through  the  sedimentary,  as  well  as  the  massive  rocks 
from  which  the  circulating  waters  have  leached  it  out  as  car- 
bonate, si'icate,  and  sulphate.  Although  the  traps  are  said  by 
Irving  to  be  devoid  of  copper,  except  as  a  secoodary  introduc- 
tion, it  would  be  interesting  to  test  their  basic  minerals  for  the 
metal  in  a  large  way,  as  has  been  so  successfully  done  by  Sand- 
berger  on  other  rocks.  It  is  probable  that  these  may  be  its 
source. 

Irving  states  that  the  coarse  basic  gabbros  of  the  system  con- 
tain chalcopyrite,  but  they  do  not  occur  near  the  productive 
mines.  The  electro-chemical  hypothesis  of  deposition  was  ear- 
liest advocated  (Foster  and  Whitney),  and  on  account  of  the 
electrolytic  properties  of  the  two  metals  copper  and  silver,  at 
first  thought,  it  seems  to  be  a  reasonable  explanation.  Still,  the 
unsatisfactory  character  of  all  exjieriments  made  in  other  re- 
gions to  detect  such  action  militates  against  it.  Pumpelly, 
however,  has  worked  out  an  explanation  much  more  likely  to 
be  the  true  one.  He  found,  on  studying  the  mineralogical 
changes  which  have  taken  place  in  the  rocks,  that  the  altera- 
tion bad  been  very  thorough,  and  that  it  had  involved  a  most 
interesting  series  of  minerals,  which  are  now  chiefly  mani- 
fested in  the  cavity  fillings.  It  is  to  be  appreciated,  as  has 
been  especially  well  shown   by  the  recent  detailed  geological 


lip 


210 


KEMP'S  ORE  J)EJ'0,sn\S. 


IHI 


sections  of  L.  L.  Hubbard,'  tbat,  in  tbe  productive  region,  the 
Keweeuawan  rocks  consist  of  a  vast  series  of  basic  lava  flows, 
with  a  few  of  more  acidic  types,  and  with  occasional  intercalated 
conglomerates.     H.  L.  Smyth"  has  also  emphasized   the  fact 
that  these  successive  lava  sheets  must  have  remained  for  pro- 
tracted })eriods  after  their  outj)ourings,    exposed  to  the  atmos- 
pheric agents,  and  to  weathiu-ing,  before  they  sank  beneath  the 
sea,  and  were  buried  under  tlie  conglomerates.     As  a  matter  of 
observation  the  upper  portions  of  the  sheets  are  notably   more 
cellular  and  decomposed  than  are  the  lower.  Two  kinds  of  amyg- 
daloids  were  indeed   recognized  by  Pumpelly, '  brown  ones,  or 
true  amygdaloids,  in  which  the  alteration  was  excessive,  and 
which  were  })robably  derived  from  cellular   lava   sheets;  and 
green  ones,  or  pseudo-amygdaloids,  which  arc  hard  and  dense, 
and  proltably   owe  their  apparent  amygdules  to  the  decom- 
position of  pyroxene,   olivine  or  feldspar  crystals.     Pumpelly 
traces  out  the    following    series   of   minerals.      The  first  to 
develop    was   chlorite.     Either    contemporaneously   with  the 
chlorite    or    next    after    it,     laumoutite,    a     by d  rated     basic 
silicate  of  calcium   and    aluminum,   resulted.      Laumontite. 
prehnite   imd   epidote,  all    non-alkaline  silicates,    next  segre- 
gated  in  the  cavities,  and   wex'e  followed  b3'   cpiartz.     They 
are  thought   to    correspond  to  the    decay   of   the     pyroxenic 
minerals  in  the  lavas.     The  copper  manifestl}'  came  in  after 
this,  and  its  deposition  seems  to  have  proceeded  along  with  the 
formation  of  a  green  chloritic  mineral,  or  green-earth,  which 
has  displaced  the  prehnite,  (piartz  and   calcite  of   the  earlier 
stages.     Calcite,  it  should  be  added,  marks  almost  every  stage 
of  the  paragenesis.     Presumably  the  reducing  action  produced 
by  the  oxidation,  of  FeO  to  Fe,..< )..  in  the  production  of  the  chlo- 
ritic "green-earth,"  caused  the  reduction  and  jirecipitation  of 
the  copper  from  some  acf.ieous  solution  of  sulphate,  carbonate 
or  silicate.     After  all  this  had  occurred  a  (jiiite  different  series 
of  minerals  (except  that  calcite  continued  to  form)  was  intro- 
duced, which  are  characteristically  alkaline  silicates.     x\ii;il- 

'  Cfcoloijivitl  Snn-i'ii  of  Miehujau,  V.,  opj).  j).  KUJ. 

»  Sciriicc.  February  1  J.  IS'Ki,  p.  3."il. 

•  Geological  Siii'vcj/ of  Michiijan.  I.,  Part  II..  14.  Ann')'.  Jour.  Sci..  Sep 
teniber.  1HT1.  f  ■■•  Anicr.  Acad.  Arts  timl  Svi(  iicrs.  XIII..  p.  ^(iS  l^i'^ 
Gcul.   W'isrousiii.  iii.,:{l. 


COPPER. 


211 


cite,  apophyllite,  datolite,  aud  last  of  all  ortboclase,  are  the  chief 
members.  Pumpell)'  regards  them  as  produced  by  the  altera- 
tion of  the  feldspars  of  the  basalts,  and  in  a  continuous  succes- 
sion of  changes  following  those  just  cited,  but  H.  L.  Smyth 
advances  the  view  that  they  and  the  co})per  came  in  after  the 
tilting  and  faulting  of  the  strata,  and  probably  in  uprising 
solutions  along  the  fissures,  which  are  illustrated  in  the  vein 
mines.  He  remarks  that  apophylite  contains  fluorine  and 
datolite,  boron,  and  that  the  mineralization  of  the  fissure  veins 
is  often  extended  in  lateral  enrichments,  where  the  fissures  cut 
porous  beds.  Pumpelly  specially  favored  the  overlying  sand- 
stones and  descending  solutions  as  sources  of  the  copper. 
Wadsworth  gives  a  resume  of  all  the  views  advanced  up  to 
1880'  aud  hnnself  favors  a  derivation  by  leaching  of  the  neigh- 
boring and  overlying  trap. 

As  stated  in  mentioning  the  great  ore-chutes  above,  the  cir- 
culations must  have  followed  the  general  lines  indicated  bj- 
theni,  so  that  it  is  evident  that  the  rich  currents  were  of  lim- 
ited extent.  The  anomalous  condition  presents  itself  of  native 
copper,  a  mineral  that  is  usually  characteristic  of  the  oxidized 
zone  of  deposits  of  sulphioes,  extending  to  great  depths  below 
tlie  ground-water  level. 

It  is  natural  to  raise  the  (]uery  as  to  the  possible  passage  of 
the  native  copper  into  sulphides  in  depth,  but  there  is  as  yet 
no  evidence  of  this  change.  Any  minerals  in  the  nature  of 
sulphides  are  extra* )rdiuaril3'  rare.  A  little  whitneyite  and 
(lomeykite  (copper  arsenides)  and  chalcocite  occur  in  the 
amygdaloid,  formerly  worked  at  the  Huron  mine;  chalcocite  has 
been  found  in  the  Bohemian  Mountains  and  in  the  Copper 
Fails  mine.  Native  copper  changes  to  chalcocite  IMt  feet  down 
in  the  Marnaisne  mine,  near  the  Sault  (L.  L.  Hubl)ard).  A 
{locket  of  melaconite.  the  black  oxide,  was  opened  in  the  early 
days  at  Copper  Harbor. 

■■i.U-t.  15.  The  discovery  of  copper  dates  back  to  the  explora- 
tions of  the  French,  who,  in  the  seventeenth  century,  left  the 

'  M.  F,,  Wadswoitli,  •  Notos  on  tlie  Geolojry  oi  t\w  Iron  iind  Copper 
Districts,  ■  a*///.  Mns.  i>f  Conij).  Zool.,  VII.,  7(i,  l'J;5.  licixirt  of  the  State 
<!iol(uiist  of  Michi(f((ii.  1892.  1(5T-1T(),  and  esi)ecial!y  l(i!».  Uw.  Also  in  a 
paniphlcl  uf  tlie  Dninlli.  Sontli  Shore  &  Atlantic  \i.  R..  isi)().  "Origin 
iunl  Moilint  Occurrence  of  the  Lake  Superior  Copper  I  )ei)osits,"  Trims. 
Amn:  Jiisl   Mi„.  Eiig.,  XXVII.,  (itjl). 


212 


KEMPS  ONE  DEPOSITS. 


m 


settlements  on  the  lower  St.  ijawrenco  and  penetrated  the  Great 
Lakes.  The  country  was  the  scene  of  a  great  mining  excite- 
ment in  the  forties.  After  many  vicissitudes  and  exploded 
schemes  the  district  settled  down  to  the  largest  jn'oduction  of 
any  American  region.  Within  the  last  few  years,  however, 
Butte,  Mont.,  has  exceeded  it.  Many  interesting  traces  of  pre- 
historic mining  were  found  by  the  early  explorers,  for  the 
copper  was  a  much-prized  commodity  among  the  aborigines. 

2.04. 1<!,  Some  important  mining  for  copper  has  been  done 
on  Isle  Royale,  along  the  Canadian  shore,  and  in  Minnesota, 
but  although  Keweenawan  rocks  are  in  great  force,  no  large 
amount  of  the  metal  has  been  found.' 

'  It  would  be  impossible  and  undesirable  to  fi;ive  in  tbis  place  comj)letf 
references  to  tbe  literatiirtv     Sncb  a  bibli(>^jrii])hy  will  he  found  in  Irvine's 
inonograpb,  and  in  Wadswoitii's.     Tbe  nioi'e  ini))()rtant  jtapers  are  given 
below,  \\\W\  some  additions  to  tbe  lists  mentioned  above. 
Bauerman,  H.,  "On  tbe   Copper  Mines  of  Michigan,"  Qimr.  Jour.  Gcol 

Soc,  XXII.,  448.  18()().     Good  account  of  tbe  minerals. 
Credner,  H..  On  tbe  geology,  etc.,  Neiirs  Jdhrbm-li,  hSi!),  p.  1. 
Foster  and  Whitney.  Re))ort  on  the  Lake  Sujierior  Copper  Lands,  IBoO. 
Hall,  C.  W..    "A    Brief  History  of   Copper  Alining   in  Minnesota,"   Bull. 

Minn.  Acad.  Xaf.  Sci..  Vol.  111..  No.  1.  p.  1(»,-.. 
"History  of  Copper  Mining  in  tiie  Lake  Superior  District,"      Engineer- 

inf)  and  Mining  .Ti)iirniil.  Marcli  IS,  lss-,\  p,  141. 
Hubbard,   L.  L.,  "Two  New  (ieological   Sections  of  Keweenaw   Point, " 

Proc.  Lake  Sup.  Min.  Innt.,  II.     Rec. 
Ii'%*ing.  R.  D.,  "  Tbe  Coi»i)erl)earing  Rocks  of  T^ake  Superior."  MoniM/nipli 

v.,  U.  S.  (rcol.  Snrrci/.  c-^pecially  p.  41i).     Rec.      Bil)liograpiiy,  p.  14. 
"Keweenaw  Point  with   Particular  Reference  to  tbe  Felsites  and  their 

A.ssociated  R<K-ks."  Geol.  Sarrci/  of  Mich..  VI.,  Part  II.,  ls!»it. 
Lane,  A.  C,  (Jeological  Report  on  Isle  Royale.  Mich.  Gcol.  Snrrcif.Xl.,  Pt.  l 
Lawson.  A.  C,  "  Notes  on  the  Occurrence  of  Native  Copi)er  in  the  Aninii 

kie  Rocks  of  Thunder  Bay,"  Anier.  Geol,  V.,  174. 
Palacbe,  Cb  .  "The  Crystalli/.ati(m  of  ('alcite  from  the  Coi)|)er  Mines  of 

Lake  Superior,"  Gcol.  SHrvci/,  Mich.,  Yl..  Part  II..  ApptMidix. 
Poole,  H.,  "Micbipicoten  Island  and  its  Copjier  Mines,"  Eng.  and  Min. 

Joni:.  August!!,  IHiC^',  p.  p^");  Sei>tember  :?.  ]».  220. 
Pumi)elly,  R.,  Gcol.  Snrrci/  of  Mich..  18T:J,  Vol.  I. 

"On  tbe  Origin  of  tbe  Copper."  Avier.  Jonr.    Sci.,  ii..  III.,  18;Mfl"). 

24y-3ri:j.  :54T    'M     Rec.     A  later  and  fuller  ])aper  is  in  Proc.  Amer. 

Acad.,  1878,   v    I.  XIH.,  p,  2;!^ 
Roniinger,  C.,  "  Copper  Regions  of  Michigan,"  Gcol.  Snrrcif  of  Micli..^ 

8."),  ISil,-,. 
Wadswortb.  M.  E. ,  Xofcf  on  the  Gcologi)  of  the  Tron  and  Copper  Di.'^triet.^ 

of  Lake  Snperior.     Cambridge,    1880.     Bibliography,    p.    l:i;i.    •''eP 

also  footnote  to  page  21 1  alK)ve. 


vol' P  Hit. 


213 


2.04.17.  Example  1'.).  St.  Genevieve,  Missouri.  Beds  of 
chalcopyrite  associated  with  chert  in  mi  j;nesian  limestone  of 
the  Cambrian  system.     St.  Genevieve  is  situated  on  the  Missis- 


%^ 


66 


4- 
i 

V 


•itt"— " 


2nd.  Magneaian  Limestona 
^Roof 

Limestone 

~>  Chert  seams 


^-|=f    Sulphuret  ore 

'~~~~  ^^^  Floor 

2nd.  Magnesian  LVmeston* 


Fig.  07. — Crosn  section  in  tJi)' St.  Heneviire  copper  mine,  illu/itrofing  the  rela- 
tions of  the  ore.  After  F.  2\'ieliolKiin,  '/'vans.  Amer.  Inxt.  Min.  Enf/.,  X.,  4-  /. 

sippi,  about  forty  miles  south  of  St.  Louis.  The  Second  Magne- 
sian Limestone  of  the  Cambrian  outcrops,  with  the  Carbonif- 
erous on  the  north,  and  more  or  less  Quaternarj''  in  the  vicin- 


A 
1 

i' 
J 
I 
I 

x;8 

I 

.,\  I' 
us 

i 


I  Limestone 

^:  Chert  and 
ore 


Chart  and 
ore 


Fia.  08. — Section  at  the  St.  Genevieve  mine,  iUuxtrittin;/  the  intimate  relations 
of  ore  and  chert.  After  F.  Nicholson,  Trans.  Amer.  Inst.  Min.  Enej.,  X.,  451. 

ity.     There  are  two   nearly  horizontal   beds  of  ore,  of  widths 
varyiiijj;  between  three  inches  and  several  feet.     They  lie  be- 

Wliitiu'v,  J.  D.,  "On  tlie  Bhu-k  Oxide  of  Coj)|)er  of  Lake  SiijHjrior,"  Froc. 

Boxton  Snc.  Xat.  Ili.-it.,  January.  184!>.  p.  103;  Anicr.  Jour.  Soi.    ii., 

Vll[.,  27:5. 
:\rft:illic  Wealtli  of  the  United  States,  p.  245.     Rec. 
Whittlcslnv,   C,    "On   Electrical  Deposition,"   Amer.  Assoc.   Adi\    Sci., 

XXIV.,  60. 
Wright,  ('.  E.,  and  Lawson,  C.  D.,  Mineral  Statistics  of  Michigan.     An 

miiil  formerly  i.ssued. 


ik 


m 


KEMP\S  ORE  DEl'061Tti. 


tweeii  cbert  seams,  and  are  associated  with  ciay  aud  sabd. 
The  ore  is  thought  by  Nicholson  to  have  been  deposited  in  cavi- 
ties formed  by  dolomitization,  much  as  is  advocated  by 
Schmidt  for  the  lead  and  zinc  deposits  of  southwest  Missouri, 
and  as  is  described  under  Example  25.  For  ten  years  the 
mines  have  not  been  operated.' 


Fig.  69. — Gcolof/kal  map  of  the  ,M<>re.iiri  or  Clifton  coppir  dixtrict  of  Arizona. 
After  A.  F.  Weiidt,  Trans.  Amer.  Lt»t.  Min.  Eiig.,  X  V    23. 

2.04.18.  Example  20.  Arizona  Copper.  Bodies  of  oxi- 
dized copper  ores  in  Carboniferous  limestones,  associated  with 
eruptive  rocks.  In  addition  to  these,  which  are  the  most 
important,  there  are  veins  in  eruptive  rocks,  or  in  sandstones, 
or  ore  bodies  of  still  different  character  as  set  forth  under  the 
several  sub-examples.    The  copper  districts  are  nearly  all  in 

'  F.  Nifliolsoii,  "Review  of  the  .St.  Genevieve  Copper  District,"  Trans. 
Amer.  Just.  Miii.  Eiuj.,  X.,  444.  B.  F.  .Sliumard,  "  OUserviitions  on  tlie 
(ieolo^y  of  the  County  of  St.  Genevieve,  Missouri,"  Traun.  St.  Lmis 
Acad.  Sci.,  I.,  40;  abstract  iu  Amer.  Jour.  Sci..  ii.,  XXVIII.,  12(1. 


COPPER. 


215 


the  southeastern  part  of  the  territory,  but  the  Black  rauge  is 
near  the  center. 


tONaFELLOW<<<J'HlLU 


Fl«.  70. — Vertical  section  of  Longfelloic  Hill,  (lifton  district,  Arizona.     After 
A.  b\   Wtndt,  I'riHin.  Anicr.  Inst.  Mill.  Eng.,  XV.,  52. 


Fig  'A  —Horizontal  sections  of  Longfellow  ore  body.    Aft  r  A.  F.  Wendt, 
Trans.  Amcr.  Inst.  Min.  Eng.,  XV.,  53. 


•^.04.19.     Example    20a.     Morenci.     The   Morenci  district, 
known  also  as  the  Clifton  or  Copper  Mountain,  lies  in  a  basin, 


21G 


KEMPS  out:  DEPOSITS. 


six  to  ten  miles  across,  whose  high  surrounding  hills  oonsist 
of  limestone,  probjibly  Lower  Carboniferous,  which  rests  oji 
sandstone,  and  this  on  granite.  The  princij)al  mines  are 
grouped  nbout  the  town  of  Morenci.  Clifton  is  seven  miles 
distant  at  the  point  where  the  smelter  of  the  Arizona  Copper 
Company  is  located.  In  the  basin  is  a  mass  of  porphyr}-,  con- 
taining frequent  great  inclusions  of  limestone.  Felsite  or  por- 
phyry (likes  are  also  abundant  in  the  surrounding  sedimentary 
and  granite  rocks.  Several  miles  to  the  east  there  is  an  out- 
flow of  late  trachyte  and  evidence  of  recent  volcanic  action. 
From  this  it  appears  that  eruptive  phenomena  are  abundant 
and  widespread. 


OPEN  CUT/ 


/^  *  PORPHYRY  '  ++  * 

*   ■*    <    * 
>...-        %^'*-     X*"    *A-t 
■*,    *•      jt  '^  A  ^ 


Fig.  73. — Gi'dlof/ical  xcction  of  the  Mctraff  viinc,  Clifcm  dintriet,  Arizona. 
After  A.  F.   Wtiidt.  Tniiis.  Anur.  IhkI.  Miii.  Kiaj.,  XV.,  36. 


2.04.20.  The  ores  are  classified  by  Henrich  as  follows: 
1.  Contact  deposits.  These  occur  in  a  zone  of  decomiKised 
and  kaolinizod  porphyry,  between  a  bluish,  tine-grained  lime- 
stone, and  solid  porphyry.  iMauy  ore  bodies,  and  probably  the 
largest,  are  directly  on  the  limestone,  while  others  are  sur- 
rounded by  the  decomposed  porphyrj'.  As  included  masses  of 
limestone,  with  associated  ore,  are  found  in  the  decomposed 
porphyry,  it  is  probable  that  these  ore  bodies  may  have  origi- 
nally replaced  such.  The  ores  are  malachite,  azurite,  cuprite. 
with  some  metallic  copper  and  melaconite,  in  a  gangue  priuci- 


CO  mm. 


»ir 


pally  of  limonite.     Wad  ih  also  freijiient.     Much  clay  of  a 
rcHidnal  charactor  occurs  with  the  ores. 

2.  Deposits  in  limestone.  These  are  closely  associated  with 
the  first  class,  and  have  apparently  formed  as  outl3'iug  bcjdics 
in  the  limestone,  as  they  are  connected  hy  ore  channels  witii 
the  princii)al  lines  of  circulation  along  the  contact.  They  ap- 
pear to  contain  more  wad  and  lime  than  the  typical  contact 
deposits. 

;{.  Deposits  in  porphyry.  These  form  sheets  and  pockets  in 
porphyry,  or  impregnate  the  soli<l  rock  itself.  They  are  oxi- 
dized at  the  surface,  but  pass  in  depth  into  chalcocite.  The 
principal  gangue  is  kaolinized  porphyry.  The  impregnated 
porphyries  are  to-day  the  chief  ore  supply. 

According  to  Weudt  the  Coronado  vein  fills  a  longitudinal 
fissure  in  a  (piartz  porphyry  dike.  It  aft'orded  chalcocite  above, 
but  ])!issed  into  (•iialc<)i)yrite  below.  Wendt  also  mentions  a 
group  of  veins  in  granite  that  likewise  aft'orded  chalcocite.' 

•^.04.'>1,  Example  -lOb.  The  Bisbee  district,  called  also  the 
Warren  district,  is  situated  in  the  Mule  Pass  Mountains  in 
southern  Arizona,  near  the  ]\Iexican  line.  The  range  runs  east 
and  west,  and  consists  of  beds  of  Lower  Carboniferous  lime- 
stone, dipping  away  from  a  central  mass  of  porpliyritic  rock. 
The  ores  are  found  in  the  cauous  on  the  south  side,  which  have 
been  formed  by  erosion,  along  the  contact  of  the  limestone  and 
])orphyry.  The}'  are  of  the  same  oxidized  character  as  at 
Morenci,  and  in  the  important  mines  occur  in  limestone. 
James  Douglass  describes  them  as  being  situated  at  a  distance 
t'roiu  the  por])hyry  of  perhaps  a  thousand  feet  or  more,  and  as 
forming  in  their  unaltered  state  huge  masses  of  pyrites  with 
copper  often  as  low  as  two  per  cent.  They  have  been  pro- 
tluccd,  as  nearly  as  one  can  judge  by  replacement  of  the  lime- 
stone, through  the  agencj'  of  solutions,  which  brought  much 
silireons  and  aluminous  matter  as  well.  It  is  natm-al  to  look 
to  the  porphyry  as  the  source  of  tlie  latter  material.     The  sul- 

'  'T.  I'ouj^lass,  "Copper  Resources  of  tlie  United  States,"  TrcDis.  Auicv. 
Inst.  J////.  Eiig.,  XIX.  6TS,  18!)0.  Rec.  "  Arizona  Copper  and  Copjier 
Mines,"  Eugr.  and  Mi n.  Jour.,  August  13,  ISSI,  p.  1(»;{.  "Clilton  Copi)er 
Klines  of  Arizona," //xV?.,  February  21,  1S80,  p.  i:%  C.  Menricli,  "The 
Copper  Ore  Deposits  near  :\[orenei."  Ariz,"  Ibid.  March  '2(),  IHST,  pp.  202, 
-li).  Rec.  A.  Wendt,  "  CopjKjr  Ores  of  tiie  Soutliwest,"  Trans.  Amer. 
Ii»it.  Min.  Eng.,  XV.,  p.  2'S.     Rec. 


218 


KEMP'S  GUI':  DEPOSITS. 


phides  pHHS  in  alteration  into  bodios  of  oxidi/cd  ore,  which  re- 
main in  the  niidHt  of  ferruginous  clay,  (.'ailed  "ledge  matter" 
l)y  Dr.  l^ouglasH.  Thoroughly  oxidized  manneH,  an  well  as  oth- 
ers whose  outer  shell  is  alone  changed,  are  known.  One  niasH 
in  the  Czar  shaft  of  the  latter  character  is  estiuiatcd  at  l,(i()(»,- 
000  tons  of  ore.  The  degree  of  alteration  does  not  apjjcar  to  he 
dependent  ou  the  vertical  position,  as  bodies  of  sulphides  are 
known  to  be  higher  up  than  thorougiily  oxidized  masses,  but 
in  this  arid  region  the  ground-water  stands  at  a  very  consider- 
able depth,  and  appears  not  to  have  been  yet  actually  reached, 
although  nnich  trouble  is  caused  by  floods  during  })cri<)ds  of 
rain.  Above  the  bodies  of  ore  empty  caves  are  usually  found, 
and  so  frecpient  is  this  association  that  when  the  prospecting 
drifts  strike  a  cave  the  miners  innnediately  sink  in  the  expec- 
tation of  striking  an  ore  body  in  depth.  Sink-holes  on  the  sur- 
face have  been  successfully  used  as  guides  in  the  same  way. 
In  the  accompanying  jjicture  of  the  mine.  Fig.  To,  the  lime- 
stones dip  into  the  hill,  away  from  the  shaft,  and  the  ores  are 
found  in  them,  and  beneath  the  valley  below. 

The  rock  referred  to  as  porphyry  above  has  been  microscopi- 
cally determined  by  A.  A.  Julien  for  Arthur  Wendt  to  be  a 
(juartz-porphyry  with  a  felsitic  ground  mass  (felsite-})orphyryof 
Julien).  Its  contact  with  the  lii,  stones  is  marked  by  a  zone 
of  kaolinization,  or  alteration,  and  is  not  sharp.  Positive  evi- 
dence of  contact  metamorphism  has  not  yet  been  recorded,  but 
the  effects  of  circulating  waters  are  pronounced.  The  results 
of  detailed  geological  study  of  the  region  will  be  awaited  with 
interest.' 

'i.O\.'Z-l.  Example  -IQc.  Globe  District.  As  in  the  other 
districts  the  most  productive  mines  are  in  limestone  near  the 
contact  with  eruptive  rocks. 

1.  Contact  deposits  in  limestone.  At  the  Globe  mines  tiie 
Carboniferous  limestone  abuts  against  a  great  dike  of  diorite, 
while  trachyte  and  granite  are  near.  Along  the  contact  tliere 
is  abundant  evidence  of  thermal  action  in  the  kaolinized  rock. 


'  .T.  Douf^lass,  "Copper  Resources  of  the  United  States,"  Trans.  Aiiwr. 
Just.  Mi)i.  Kiiij..  XIX..  nrs.  1S!)0.  liec.  ■•  Tlie  (•()pi)er  Qiu'cii  Mine,"  New- 
York  lueetiug  of  tlie  Aiucr.  Inst.  Miii.  Einj.,  February,  ISi)!).  See  E lift 
and  Min.  Jour.,  February  25,  18!»!»,  \>  '2:',0.  A.  Weialt.  "Copper  Ons 
of  the  Southwest,"  Trans.  Anirr.  Jii.sf.  Min.  En;/.,  XV.,  p.  52.     Kee. 


■  ■■;-;  ■  ■  "^ 


*5 


cq 


O* 


■~( 


in 


iHP' 


I'OPPKh'. 


219 


The  great  bodies  of  tjxidized  ores  are  foiiud  on  this  contact  aud 
extend  out  into  the  liineHtone.  The  one  on  the  Globe  chiini  is 
described  liy  Wendt  an  resembling  a  great  ciiinniey. 

'2.  A  tissure  vein  in  nandstone.  containing  arsenical  and 
iiutimonial  copper  ores,  and  kncnvn  as  tbn  Old  Dominion,  was 
formerly  worked. 

:i.  Fissure  veins  in  talcose  slate  and  gneiss,  aud  tilled  by  a 
(jiiartz  gangue  with  bunches  of  malachite  and  azurite  (New 
York  and  Chicago  mines),  and  now  no  longer  worked. 

4.  Numevoi.-*  small  veinlets  forming  a  stock  work,  in  gneiss 
near  a  dike  of  diorite,  which  is  crossed  by  a  dike  of  trachyte. 
Tliese  are  known  as  the  Black  Cojjper  (ironp.  The  oies  are 
too  low  grade  for  profitable  exploitation.  Of  greater  interest 
are  the  bodies  of  chrysocolla,  found  in  the  wash  down  tiie  hill 
from  the  outcrop  of  the  veins,  and  evidentlj'  due  to  the  super- 
ficial drainage  of  the  stockvvorks.  Similar  bodies  of  ore, 
though  not  chrysocolla,  were  found  at  Ivio  Tinto,  in  Spain.' 

•*. 01. •.»:{.  Example  'HUl.  Santa  Kita  District.  Although 
in  New  Mexico,  this  district  has  much  in  connnon  with  those 
already  mentioned.  A  great  dike  of  felsite  cuts  limestones, 
and  along  the  contact,  as  well  as  in  the  felsite  itself,  copper 
ores  are  found. 

1.  Contact  deposits  in  limestone.  These  afforded  the  nsual 
u.xidized  ores,  but  were  not  found  to  extend  to  any  great  depth, 
and  while  for  a  time  prodnctive,  they  were  soon  exhausted. 

•.'.  Deposits  in  felsite.  Tliese  consisted  of  pellets  and  sheets 
of  native  copi)er  in  the  dike  itself,  which  were  oxidized  to 
('uprite  near  the  surface.  (Cf.  Lake  Superior  amygdaloids, 
Kxauiple  is.)  They  were  worked  by  tlie  Mexicans  in  the  early 
l)art  of  the  present  century." 

'  J.  Douglass,  "  Copper  Resources  of  tlie  United  States,"  Truns.  Avier. 
/-'.s'.  .l//».  i;»(/.,  XIX.  (iTS,  IH'.K).  Rec.  ••  Tiie  (ilobe  District,"  i!:»(/.  oju/ 
Mill.  Jinir.,  April  St.  188t,  p.  243.  W.  E.  Newberry,  "Notes  on  the  Pro- 
'liictiDii  of  Copper  in  Arizona."  School  of  Miiica  Qiiorfcrhf.  VI..  ;!70.  A. 
Tii|)i(i|.  'Occnrrence  of  Cold  and  Silver  in  Oxidized  Copper  Ores  iu 
Arizoiiii,"  Eng.  and  Miii.  Join:,  June  Ki,  188;$,  p.  4;r).  A.  Wendt,  "Cop- 
jiiT  Ores  of  the  Sontliwost."  Troiis.  .\iiicr.   Tiint.  Miii.  Eikj..  XV.,  jt.  (iO. 

■'  A.  F.  Wendt,  "Cojiper  Ores  of  the  Southwest."  2'raiis.  Avicv.  Inst. 
Mill.  Eii!i.,XV.,  27.  Wislizeiuis.  "On  the  Santa  Rita  Mines:  Memoir  of 
11  Tour  in  Northern  Mexico,  1846-47,"  p.  47;  Aiiier.  Join:  Sri.,  ii.,  VI., 
;>:.,  IS  IS 


2-^0 


KEMPS  on/-:  DEPOSITS. 


2.0-1.24.  Example  20e.  Black  Range  District.  This  is  now 
the  leading  copper  producer  of  Arizona,  and  has  come  intc 
great  prominence  within  a  few  years.  In  its  geological  rela- 
tions it  appears  to  be  more  like  the  California  deposits  than 
any  others,  but  there  are  as  yet  but  few  recorded  details.  It 
appears  that  there  is  a  great  dike  of  more  or  less  porphyritic, 
dark  green  rock  that  has  been  extensively  fractured  along  a 
broad  line  of  dislocation  for  several  miles.  The  fractured 
zone  strikes  north  lO*^  west,  and  outcrops  about  r),S!00  feet 
above  tide.  The  writer  has  examined  thin  sections  of  the  dike- 
rock,  which  is  locally  called  diorite,  but  the  specimens  at  hand 
were  too  thoroughly  decomposed  to  admit  of  close  identifica- 
tion. No  dark  silicates  were  visible,  and  chloritic  products 
alone  indicated  their  former  presence.  Broadly  rectangular 
feldspars  were  the  chief  minerals,  but  they  were  too  badly 
altered,  even  to  indicate  their  character,  although  no  positive, 
polysynthetic  twinning  could  be  detected.  Quartz  was  com- 
mon. In  de))th  sheared  dike  rock  is  met  that  reseuibles  sla^e. 
The  ore,  which  embraces  both  bornite  and  cbalcopyrite,  fills 
the  cracks  and  larger  fissures  and  impregnates  the  slaty  rock. 
There  is  some  galena  present,  arid  earthy  lead  sulphate  ha-; 
resulted  from  it  in  the  gossan.  The  ore  carries  both  gold  and 
silver.  The  inaccessible  situation  of  the  mines  long  bindncil 
their  development,  but  now,  with  a  mountain  railway  to  give 
them  an  outlet,  they  are  very  productive.  They  are  operated 
bj'  the  United  Verde  Company,  and  are  about  20  miles  west  of 
Pre.scott.^ 

2.()-t.2.">.  Example  20/.  Copper  Basin.  Beds  of  closely  tex- 
tured conglomerate  arid  sandstone,  resting  on  granite  aiid 
gneiss,  and  having  a  cement  of  copper  carbonates.  Copper 
Basin  lies  about  twenty  miles  southwest  of  Prescott,  and  is 
formed  by  a  depression  in  greatly  decomposed  granite,  whieh 
is  travori-'ad  by  numerous  small  veinlets  of  co})j)er  ores.  The 
granite  is  pierced  b}'  porphyry  dikes,  and  covered  by  the  sedi 


'  J.  F.  Bl,indy,  "Tlie  Mining  Region  Aronnd  Prescott.   iVriz,"  Travft 
Jiiirr.  lust.  Mi)i.  £i,(j.,  XI.    2m.     U.  K.  (iilbert.  "On  the  (Jetienil Geology 
of  the   Bhick  I»Ioiiiitain   Districl,"  Wlt'^clcr's  Si'mi/.   III.,  p.  :{■").     A.  K. 
Marvine,  "Brief  Details  of  the  Verde  Valley,"  Wheeler's  Snrvei/.  III.,  l' 
•Jt.'il.     A.  F.  Weudt,  "  Copper  Ores  cf  the  Southwest,"  Trans.  Ana"'.  Ji>-" 
Mil    Emj.,  XV.,  W.).     Rec. 


wi^lFiiffilK 


COPPER. 


231 


;.>ly  tex- 

ite    '^i'*^ 
Copper 

and  i^ 

'S.     Tilt' 
be  stnli- 

il  Geology 
:i5.     A.K- 

•//.  iii.i; 


mentary  conglomerates  and  sandstones  into  which  its  copper  is 
thought  by  Blake  to  have  partially  leached  and  precipitated  as 
a  cement.  Reference,  by  way  of  comparison,  may  be  made  to 
tlie  Lake  Superior  conglomerates,  in  which,  in  part,  the  native 
copper  serves  as  a  cement.' 

2.0-l:.2(i.  There  are  numerous  other  copper  districts  in  Ari- 
zona of  minor  importance,  or  entirely  undeveloped,  but  the  ex- 
amples above  cited  probably  illustrate  the  occurrences  quite 
fully.  Those  not  referred  to  are  of  sporadic  development. 
Copper  jjrospects  are  known  in  the  Grand  Caiion  of  the  Colo- 
rado, and  have  received  some  attention.''  Mention  should  also 
be  made  of  the  mine,s  in  Lower  California,  opposite  Guaymas, 
a  brief  description  of  which  will  be  found  in  Wendt's  paper.'' 
The  copper  ores  impregnate  beds  of  submarine  volcanic  tulf, 
and  are  unique  in  their  geological  relations. 

Much  copper  is  now  met  in  depth  at  Leadville,  Colo.  The 
geology  of  the  mines  is  set  forth  under  Lead-Silver. 

•3. 04. '^7.  Example  •iOfy.  Crismon-Mammoth,  Utah.  In  the 
Tiutie  district,  Juab  Count}',  are  three  great  ore  belts,  in  ver- 
tically dipping  dolomitic  limestone,  as  more  full}'  set  forth 
under  "Silver"  (Example  ;35o).  One  of  these,  the  Crismon- 
Mammoth,  contains  ores  that  bear  silver,  gold,  and  copper  in 
proportions  of  about  equal  value.  They  have  been  a  very  diffi- 
I'ult  mixture  to  treat  successfully.  Of  late  considerable  copper 
lias  been  produced,  placing  the  ore  deposits  among  those  deserv- 
ing mention.  The  Crismon-Mammoth  vein  or  belt  covers  a 
maximum  width  of  TO  feet,  and  runs  o(K)  feet  on  the  strike, 
(lipping  r.o'  west.  The  ores  seems  to  have  been  deposited  along 
the  bedding  planes,  though  often  cutting  across  them.  The  pro- 
ductive portions  are  found  in  richer  chutes  or  chimneys,  amid 
much  low-grade  material  and  gangue,  and  are  of  all  shapes 
aud  sizes,  from  25  feet  in  diameter,  down.     The  Copperopolis 

'  W.  p.  Blake,  "Tlie  Coi)i)er  Deposits  of  Copier  Basin,  /a-izona,  and 
their  Origin."  7'j-(/»s.  Amci:  Jiinf.  Min.  Eiiij.,  XVII.,  4T!>. 

'J.  F.  Blaudy,  "On  Arizona  Copiwr  nei)osits."  Eng.  aud  Miii.  Jour., 
1697,  \c!.  LXIV.,  )).  it:. 

'See  also  M.  E.  Saladin,  "Note  snr  les  Jliues  de  Cuivre  du  Boleo 
(Basse  t'aliforuie),"  Bull,  dc  la  Societc  dc  l' Industrie  Miueralc,  '.i  Serie, 
VI.,  .'i.  iHli. 


232 


KEMP'S  ORE  DEPOSITS. 


is  thought  to  be  on  the  same  belt,  and  is  a  neighboring  location 
of  similar  geological  structure  and  ores.' 

A  very  important  body  of  chalcocite  was  discovered  in  IS'.tH 
in  Bingham  Canon,  whose  geological  relations  are  similar  to 
those  described  for  the  lead-silver  ores  under  2.08."-io.  Its  loca- 
tion was  on  the  Highland  Boy  claim. 

2.04.28.  Wyoming,  Idaho,  Washington.  Oxidized  ores 
have  been  exploited  to  some  extent  at  the  Sunrise  mines,  in  the 
Laramie  Range,  W3'oming.  Iron  ores  are  in  the  same  region 
(see  under  Hematite).  Other  copper  prosi)ects  have  been  opened 
in  the  Wood  River  region  in  northern  Wyoming,  and  at  other 
points,  but  the  geological  relations  have  not  yet  been  described. 

2.04.20.  In  the  extreme  western  border  of  Idaho,  near  the 
Oregon  line,  the  Seven  Devils  district  has  been  located  and 
developed  to  a  considerable  degree.  Intrusions  of  diorite  have 
pierced  a  white  marble  and  upon  the  contacts  and  upon  in- 
clusions have  developed  extensive  aggregates  of  garnet,  epidote 
and  specular  hematite,  together  with  very  considerable  amouuts 
of  bornite.  Green  prophyritic  dikes  are  also  present.  Lind- 
gren  regards  the  ore  as  formed  by  pneumatolytic  processes  set 
up  b}'  the  diorite.  As  also  remarked  by  Lindgren  the  type  of 
ore  body  is  known  in  Mexico,  and  indeed  a  number  of  cases 
have  come  to  the  notice  of  the  writer.^ 

Not  a  few  copper  prospects  have  been  located  in  Washington, 
but  they  are  as  j'etof  somewliat  undemonstrated  valie.  North 
of  Lake  Chelan  in  the  Stehekin  district  copper  sulphides,  pyrites 
and  mispickel  impregnate  brecciateil,  andesitic  dikes  in  marble.' 
A  vein  in  King  County*  is  described  as  occiu'ring  in  syenite, 

2.04.00.  Example  21,  Copper  ores  in  Triassic  or  Permian 
sandstone.     They  occur  as   oxidized  ores,  with  native  silver. 


'  O.  J.  Ilollister,  "(Told  iind  Silver  Miiiinj^  in  Utah,"  Troim.  Aincr.  lii.-il 
Mill.  Eiig..  XVI.,  p.  10.  D.  B.  Huntley,  r<>)ith  CV(/.s».s'.  Vol.  XIII.,  i).  1  >"i 
A  rejioit  on  the  Tintio  Di.strict  is  in  piesis  with  the  U.  S.  ileal.  Sum  i/. 
hut  is  not  avaiU;!    j  at  this  writing. 

^  R.  li.  Packard.  "Ou  an  Occuri-enoe  of  f'ojiper  in  Western  Tdahn. ' 
A)itei:  Jonr.  Sri.,  t)etol)er,  lSi).j,  2!)S.  W.  IJudgren,  "Cojipcr  Deposits  oi 
tiie  Seven  Devils,"  Mining  and  Scientific  PrenH,  ¥eh.  A.  iSJHt.  125.     Rei-. 

'  As  learned  from  tiie  writer's  friend.  Charles  Of,  f-oni  whom  material 
has  heen  obtained  anil  examined. 

^  R.  II.  Norton,  "A  Washington  C'op[)er  Deposit,"  Eiitj.  and  Miit.  Jour , 
Februarv  11,  ISltit,  ITJJ. 


COPPER. 


22a 


and  clialcocite  in  contact  deposits  in  Triassic  and  Permian 
sandstones  at  tlieir  junction  \\\i\\  diabase  or  gneiss,  or  as  dis- 
seminated masses  replacing  organic  remains.  Copper  ores  are 
very  common  throughout  the  estuary  Triassic  rocks  of  tho 
Atlantic  coast,  and  although  formerly  much  mined,  they  are 
uow  proved  valueless,  and  of  scientific  interest  only. 

•.'.04, ;U.  Example  :2h<.  Contact  deposits  in  sandstone  at  its 
junction  with  diabase.  These  include  tlie  New  Jersey  ores, 
vigorously  worked  before  the  Revolution.  They  consist  of  the 
carlKinates,  of  cuprite  and  of  native  copper,  disseminated  through 
sandstone  near  tlie  trap.  The  Schuyler  mines,  near  Arlington, 
N.  J.,  and  several  other  openings  near  New  Brunswick,  N.  J., 
are  best  known.     These  Triassic  diabases  often  show  chalcopy- 


FlG.  74. — ('roxH  .lecfioii  of  the  Srlun/lcr  Copper  viini',  New  Jcmei/.     a,  trap; 

b,  naiiilxtone:  c,  shaleii;  thu  hliwk  xhndiiKj,  nipprr  .nrx.     After 

\.  II.  Barton,  U.  S.  Geol.  ,'^iirrti/,  BnU.  ^Sl,  p.  57. 


ritf.  and  it  is  probable  that  the  copper  came  from  this  or  from 
cojiper  in  the  augite  of  the  rock,  in  accordance  with  Sand- 
bei'jj;er's  investigations.  The  deposits  are  unreliable,  and  ex- 
c't^'pt  at  a  very  early  period  have  never  been  an  important  scturce 
of  ore. 

'IM.'.V2.  Example '21/>.  Contact  deposits  in  sandstones  at  the 
junction  with  gneiss.  .^1  uumljer  of  deposits  were  formerly 
\vorl<H-i  of  this  character,  especially  at  Bristol,  Conn.,  and  at 
tlie  Pu'kiomen  mine,  Petmsylvania,  The  mine  at  Bristol, 
Conn.,  is  a  well-tnarked  contact  de])Osit,  on  the  line  oetween 
tlie  Triassic  sandstone  and  the  schistose  rocks.  The  contact 
runs  nortlieast  and   southwest,  has  suffered  great  decomposi- 


224 


KEMPS  ORE  DEPOSITS. 


tion  from  mineral  solutions,  and  has  been  largely  kaoliuized. 
A  broad  band  of  this  decomposed  material,  ;50  to  120  feet  wide, 
lies  next  the  sandstone,  and  contains  disseminated  ore.  Then 
follow  micaceous  and  hornblende  slates,  often  with  hornes  of 
gneiss.  The  slates  are  much  broken  by  movements  tliat  have 
formed  cavities  for  the  ores.  It  is  reasonable  to  connect  the 
stimulation  of  the  ore  currents  with  the  neighboring  trap  out- 
breaks. Unusually  fine  crystals  of  chalcocite  and  barite  have 
made  the  mine  famous  the  world  over.  While  at  one  time  a 
source  of  copper,  for  many  years  it  has  been  unproductive.' 

2.04. ;5;5.  Example  21c.  Chalcocite  and  copj)er  carbonates 
replacing  vegetable  remains,  etc.,  in  the  Permian  or  Triassic 
sandstones  of  Texas,  New  Mexico,  and  Utah.  In  the  Permian 
of  northern  central  Texas  are  three  separate  copper- bearing 
zones,  forming  three  lines  of  outcrop  that  extend  in  a  general 
northeasterly  direction  over  a  range  of  about  three  coimties. 
The  ore  is  largely  chalcocite  in  beds  of  shale,  and  often  re- 
places fragments  of  wood.     It  may  be  available  in  time." 

At  various  places  in  Utah  and  New  Mexico  (Abi(iuiu,  N.  M., 
Silver  Reef,  Utah),  the  sandstones,  as  reported  by  Newberry 
and  others,  have  copper  ores  disseminated  through  them  and 
deposited  on  f' ssils,  at  times  with  associated  silver  (Utali). 
The  copper,  whether  coming  from  the  waters  along  the  shore 
line  or  from  subterranean  currents,  was  precipitated  by  the 
organic  matter.  (See  also  under  "Silver,"  in  Utah.)  The.^e 
deposits  are  not  yet  sources  of  copper.^ 


■  L.  C.  Beck,  "Notice  of  the  Native  Copper  Ores,  Copper,  etc.,  near 
New  Brun.swick,  N.  J.,  '  Aiucr.  Jonr.  Sci.,  i.,  XXXVI.,  107.  (}.  II  Cook. 
Gcol  of  K  J..  ISfiS.  p.  (i7.-»;-  also  L..C.  Beck.  Ibid.,  218-224.  J.  d.  Peiri 
val,  livp.  oil  Gcol.  of  Conn.,  p.  77.  C  A.  Sliaeffer,  "Native  Silver  in  New 
Jersey  Cop])er  Ore,"  Eng.  and  Min.  Jour..  February,  1HS2.  |).  !K).  t'. 
U.  Sliepanl.  Orol.  of  Conn..  1S:V7,  p.  47.  B.  Silliir.an  and  .1.  D.  Wliitiu'v. 
"  Notice  of  the  (Jcoloj^ical  Position  and  Character  of  the  Coiipcr  Mine  at 
Bristol.  Conn.,"  Amer.  Jour.  Sci..  ii.,  XX.,  im.  J.  I).  Wliitney,  Mitnllii' 
Wealth.     Rec. 

"  W.  F.  Cnninilns.  "  Rejtort  on  the  Permian  of  Te.\as  and  its  Overlying' 
Beds."   Fir.^t  Ann.    Pep.    7V,(v/.s   Geol.    Snrrei/.    p.   liHi.     .1.    F.    Fuiiniiii. 
"  Geology  of  the  Copiier  Region  of  Northern  Texas  and  Indian  Terrilnry. 
TraiiH.  N.  Y.  Acad.  Sci..  ISHl-S:?.  j).  l.'). 

'  F.  ]\I.  F.  Cazin.  "  The  Origin  of  the  Copper  and  Silver  Ores  in  Trias-ii' 
Sand  iiock.  ■  Eng.  and  Min.  Jonr.,  April  80,  IHSd;  Decend)er  11,  1HN(». 
"The  Naceniieuto   Copper   Deposits,"  i?)jV/.,  Angnst  22.  ISS.").  p.  r.M. 


\. 


COPPER.  225 

'Z.()\.U.  Copper  production  in  188:i,  18'.)0  and  1897,  in  tons  of 
2,<iOO  pounds  each: 

188-i.  1890.  1807. 

Lake  Sii]H>nor 28,r.78  50,373  72,ft20 

Montiuiii 4,529  5(5,490  118,579 

Arizona 8,992  17,398  40,510 

Colorado 747  441  4,719 

New  Mexico , 484  425               

California 413  11  7,065 

Utah 303  503  1,927 

Elsewhere 1,412  3,906  2,874 

Copper  sulphate 6,501 

45,408  129.546  255.095 

The  figures  indicate  in  general  a  vast  increase  in  production, 
and,  above  all,  the  advance  of  Montana,  For  detailed  statis- 
tics Tlie  Mineral  Industry,  issued  annually  by  the  Scientitic 
Publishing  Company,  New  York,  and  the  Annual  Reports 
of  the  Director  of  the  U.  S.  Geological  Survey  are  the  chief 
books  of  reference. 

W.  Jackson,  Rep.  Director  of  the  Mint,  1880,  j).  334.  J.  S.  Newberry, 
"Copper  in  Utah,  Triassic  Sandstcnes,"  Eiuf.  atiiJ  Min.  Jour..  Vol.  XXXI., 
p  5.  Also  October  23,  ISSO.  p.  2()9;  January  1.  IHSl,  p.  4.  See  also  Tnitli 
Census,  Vol.  XIII.,  Precious  Metals,  pp.  40,  478.  C.  M.  Rolker,  "The  Sil- 
ver Sanil-itiine  District  of  Utah,"  Trans.  Anicr.  Inst.  Min.  En;/..  IX..  21. 
R.  P.  Kothwell,  (piotcd  in  Tenth  Census,  Vol.  XIII.,  p.  478.  B.  Sillinian. 
"The  Mineral  Regions  of  Southern  New  Mexico,"  Trans.  Amer.  Inst. 
Min.  Eng.,  XVI.,  427. 


1 

^1 

CHAPTER  V. 

LEAD    ALONE. 

2.05.01.  The  deposits  of  lead  are  treated  in  three  different 
classes,  according  as  they  i)roduceor  have  produced  lead  alone, 
lead  and  zinc,  or  lead  and  silver.  Of  late  years  the  lead-silver 
ores  have  been  the  great  source  of  the  metal.  Only  the 
southeast  Missouri  region  is  of  much  im|)ortance  among  the 
others,  although  considerable  lead  is  also  obtained  in  associa- 
tion with  zinc, 

LEAD  SERIES. 

Pb.  S. 

Galena,  PbS 86.6  13.4 

Ceiussite,  Pbt'O,, 77 . 5  .... 

Anglesite,  PbSO^ 68.3 

PyrDiiiorpliite,  PIj-iPoOh  +  I/SPIjCL,.  7(5.3(5  

Earthy  iiiixturt-s  of  tliese  last  three  and  liujouite. 

2.05.0'?.  Example  22.  Atlantic  border.  Veins  of  galena 
in  the  Archean  rocks  of  the  States  along  the  Atlantic  border; 
also  others  in  Paleozoic  strata,  as  described  in  the  sub- 
examples. 

2.05.0:3.  Example  22a.  Veins  in  gneiss  and  crystalline  lime- 
stone, sometimes  with  a  V)ariteor  calcitegaiigue.  These  depos- 
its were  vigorously  exploited  forty  years  ago  or  more,  but  have 
since  been  of  small  importance  other  tliau  scientific.  They 
may  he  described  best  by  districts,  as  thej'  hardly  deserve  a 
greater  prominence. 

2.05.01.  (1)  St.  Lawrence  County,  New  York.  Veins  with 
galena  in  a  gangue  of  calcite  in  Archean  gneiss.  Those  near 
Rossie  are  perhaps  best  knoAvn.  especially  for  their  unusually 
interesting  calcite  crystals.  There  are  numbers  of  veins  in  the 
district  wliich  are  notable  in  that  the  galena  is  without  zinc  or 
iron  associates.    The  lead  carries  a  verv  small  amount  of  silver, 


LKAI)  ALONK. 


227 


]S  with 
se  iK'iiv 

g  111  the 

ziiic  or 

i^ilver, 


not  enough  to  separate.  Hornbleude  and  mica  schists  occur  iu 
the  same  region,  and  tlie  Potsdam  sandstone  is  not  far  removed. 
A  few  minor  veins  cut  the  Trenton  limestone  near  Lowville, 
Lewis  County,  sometimes  with  fluorite  for  a  gangue.' 

•>*.05.0o.  (2)  Massachusetts,  Connecticut  and  eastern  New 
York.  Veins  of  galena  with  more  or  less  chalcopyrite  and 
pvrite  in  a  quartz  gangue  in  gneiss,  slates,  limestones  or  mica 
schists.  The  mines  near  Northampton,  Mass.,  were  formerly 
well  known,  although  never  productive  of  a  great  deal  of 
metal;  hut  as  there  is  a  large,  prominent  vein,  it  attracted 
attention.  There  are  numerous  others  in  the  same  region. 
Veins  also  occur  at  Middletown,  Conn.,  where  much  silver  is 
said  to  be  found  in  the  galena.  More  recently  {circa  1873)  at 
Newburyport,  Mass.,  argentiferous  galena  attracted  attention, 
but  was  not  of  any  importance.  Other  veins  are  known  at 
Lubeck,  Me.,  and  in  various  parts  of  New  Hampshire  and 
Vermont.  For  a  time  small  lodes  in  the  slates  of  Columbia 
County,  New  York,  were  unsuccessfully  exploited,  of  which 
the  Ancram  mine  is  of  historic  interest.  Although  these  galena 
veins  are  numerous,  they  are  not  to  be  taken  too  seriously." 

2.05.0(j.  (;5)  Southeastern  Penus3'lvania.  Veins  on  the 
contact  of  Archean  gneiss  and  Triassic  sandstone  and  diabase. 
These  weie  referred  to  under  J^Lxample  21/>.  As  noted  by  Whit- 
ney, the  copper  is  especially  strong  in  the  sandstone,  and  the 
lead  in  the  gneiss.  Trap  dikes  are  abundant,  and  the  eruptive 
phenomena  in  connection  with  them  may  have  occasioned  the 
activity  of  the  circulations  which  tilled  the  veins.  The  Wheat- 
ley  mine  is  best  known.     It  has  ati'orded  a  great  variety  of  lead 

'  I..  C.  Beck,  Minvraloqy  of  New  York:  p.  4.").  E.  Emmons,  "Geologj-^ 
of  tlH>  Second  District,"  k  Y.  Gcol.  Siirn)/.  IH-l'.'.  C4.  Hadley,  "Crystal- 
lizt'il  Carbonate  of  Lead  at  Rossie,"  Ainer.  Join:  Sci.,  ii.,  II.,  IIT.  F.  L. 
Niison,  "Calcite  I'ron^  Rossie,"  Bull.  4,  N.  Y.  State  Mnscinii.  ISSS.  J.  D. 
Whiliun-,  Metallic  Wealth.     Rec. 

'  15.  K.  Emerson,  Geology  ol  old  Hampshire  Co..  ^lass..  comprising 
Fianklin,  Hampshire  and  Hampden  cimntics.  Monoiiraph  XXIX,  U.  S. 
(tclI.  Siiririj.  See  also  Bulletin  IJG. — Idon.  C.  A.  Lee,  ■•Notice  of  the 
Aiicrani  Lead  Mine,"  Amer.  Jour.  Sci.,  i.,  VIII.,  347.  A.  Nash,  "Notice 
ot  the  Lead  Mines  and  Veins  iu  Hampshire  County.  Jlassaclnisetts," 
Amer.  Jniir.  Set.,  i.,  XII.,  238.  R.  H.  Ricliards,  '  The Newlmryport Silver 
Mines,"  7Va??.9.  Amer.  Inst.  Min.  En(i.,l\\.,  443.  H.  Silliman,  at  Soutl) 
iinipton,  Mass  Brnee's  Journal  of  Mineralogy,  I.,  (iii.  J.  U.  Whitney, 
Metallic   Wraith. 


228 


KEMP'S  ORE  DEPOtilTS. 


minerals,  especially  pyromorphite.     The  mines  have  not  been 
worked  in  years.' 

^.05.07.  (4)  Davison  County,  North  Carolina.  Veins  in 
talcose  slate  were  formerly  exploited,  but  are  now  little  kn(jwn, 
except  as  having  furnished  beautiful  crystals  of  oxidized  lead 
minerals.^ 

2. 05. OS.  Example  ^'V).  Sullivan  and  Ulster  Counties,  New 
York.  Veins  along  a  Liie  of  displacement  on  the  contact 
between  the  Hudson  River  slates  and  the  sandstones  of  the  ]\Ie- 
dina  stage  (Shawanguuk  grit),  carrying  galena  and  chalcopy- 
rite  in  a  quartz  gangue;  or  else  gash  veins  filled  with  tlie  samn 
in  the  grit.  These  mines  formerly  produced  considerable  lead 
and  copper,  but  are  now  best  known  for  the  excellent  quartz 
crystals  which  they  have  furnished  to  all  the  mineralogical  col- 
lections of  this  and  other  lands.'' 

2.05.00.  Example  23.  The  Disseminated  Lead  Ores  of 
Southeast  Missouri.  Gal«na,  accompanied  by  varying  amouuts 
of  nickeliferous  pyrite,  disseminated  through  dolomitic  lime- 
stone of  Lower  Silurian  or  Cambrian  age,  its  determination  be- 
ing in  dispute.  The  dolomitic  limestone  is  called  the  St.  Jo- 
seph limestone  by  Arthur  Winslov/,*  who  considers  it  Lower 
Silurian.  C.  R.  Keyes''  has  designated  it  the  Fredericktowii. 
and  classifies  it  with  the  Cambrian.  As  shown  in  the  accom- 
panying map,  which  is  based  on  one  by  Winslow,  the  mining 
districts  are  distril)uted  along  a  line  running  west  of  north. 
At  the  north  is  Bonne  Terre,  the  most  productive  of  all  up  to 
the  present.  A  few  miles  south  is  the  Flat  River  district,  in- 
cluding Desloge.  The  next  is  Doe  Run,  and  then  after  a  con- 
siderable interval  Mine  la  Motte.  Recently  prospects  have 
been  opened  near  Fredoricktowu.  Much  drilling  has  been  done 
between  these  centers,  but  without  notable  results.  The  geo- 
logical relations  are  simple.     On  the  couth  and  southwest  are 

'  H.  D.  R<).<;ers.  Gciil.  of  hini..  II..  TOl :  also  Anier.  Joiit:  Sci.,  ii.,  XVI., 
423.     J.  D.  Whitney,  JJetallic  Wealth,  p.  :3it(i. 

'  .I.e.  Booth,  "Analy.ses  of  Various  Ores  of  Lead,  etc.,  from  King's 
Mine,  Davison  County,  Nortli  Carolina,"  Atnei:  Jour,  ScL,  1.,  XLL,  ;i48. 
\V.  C.  Kerr,  Geol.  of  North  Carolina,  p.  28'J. 

'  J.  D.  Whitney.  JMallic  Wealth.  W.  W.  Mather,  N.  Y.  State  Survey, 
Report  on  Firi<t  District,  :5.")8. 

*  Bull,  l.'i,:',  U.  S.  a  col.  Snrrcii,  p.  11. 

'  "Mine  la  Motte  Sheet,  "  in  Mo.  Gcol.  Survey,  Vol.  IX.,  Report  1.  p.  l"*- 


LEAD  ALONE. 


229 


te  Survey • 


the  Archean  granites,  porphyries  and  diabase  dikes,  earlier 
mentioned  in  conuection  with  the  specular  heniatitt's  of  Iron 
Mountain  and  Pilot  Knob.     Scattered  knobs  of  them  are  also 


GEOLOGICAL  JLVP 
OF  THE 
80VTIIE.(S'n:K>  MISHOIRI 
DISSEJII.NATKl)  LE.4I)  OIIG  »IU-DISTRII'T 


Diimaruk' 


Potosi 
^=^Linu'8tone 

. .  I     .       Jf'~^  St. Joseph 
h.lunun  ^t^::=i  Li,,,,,,  j„, 

isundiitone 


Arc  Loan 


Fig.  75. 


mot  to  the  (^antward.  On  the  «;ranites  and  porphyries  rests  the 
l>a  Motte  sandstone,  of  variable  thickness,  but  possiljly  reach- 
ing -iui'  feet,  according  to  Winslow.  Conformably  on  the  sand- 


i 


230 


KKMl'.S  (J III':  DEPOSITS. 


ytuuo  lies  the  St.  Joaoph  doloniitic  limeHtoiie,  i\w  ore-boar iii^ 
fonnatiou.  It  varieH  from  "^ 00  feet  at  JMiiie  la  Motte  to  (Kio 
feet  at  Bonne  Terre.  It  varies  from  slialy  to  massive  Htriict- 
nres.  and  is  often  coarHely  yrauular  in  texture.  In  roclc  of 
the  latter  character,  and,  in  the  wouthurn  distriotH,  uHiially  not 
far  above  the  sandstone,  is  found  th3  ore.  At  Bonne  Terre, 
however,  the  ore  is  a  long  distance  above  the  base.  The  ore  is 
f^aleua,  often  mingled  with  more  or  less  jjyrites,  and  as  a  r-iio 
it  is  disseminated  througii  the  limestone  so  as  to  form  an  intc 
gral  part  of  the  rock.  It  also  forms  sheets  sometimes  aloii",' 
joints  and  stratification  planes,  and  seems  to  favor  the  darker 
or  more  bituminous  varieties  of  the  dolomite.  At  Mine  la 
Motte  certain  "diggings"  or  mines  seem  to  have  some  conne(!- 
tion  with  a  local  fault,  hut  others  do  not  indicate  such  rela- 
tions, and  elsewhere  small  fissures,  or  joints,  often  so  tight  as 
only  to  be  revealed  by  the  dropping  of  water,  are  the  only 
cracks  of  any  kind  apj)areut.  The  St.  Joseph  formation  lies 
very  Hat,  and  is  practically  devoid  of  fossils.  Above  it  conies 
a  cherty  limestone,  called  the  Potosi  by  Winslow  (Leseur  by 
Keyes).  It  is  widespread,  but  has  no  immediate  connection 
with  the  ore. 

The  ore  bodies  are  in  the  nature  of  impregnations  of  the  wall 
rock  which  extend  fairly  parallel  with  the  stratification  and 
are  of  varying  thickness.  They  fade  out  gradually  into  lo'v 
grade  or  barren  rock.  Thoj'  may  l)e  cut  at  several  horizons  by 
the  shafts  or  drill  holes.  One  at  Bonne  Terre  has  been  mined, 
according  to  Winslow,  over  an  area  nearly  three-quarters  by 
one  half  of  a  mile,  and  ore  is  known  through  ahnost  'l'^^)  feet 
vertical  thickness.  The  yield  to  date  has  been  about  a  (juarter 
of  a  million  tons  of  lead.  Throughout  the  districts  tlie  shafts 
are  not  deep,  seldom  reaching  400  feet.  The  ore  as  mined  con- 
tains from  7  to  10  per  cent  galena,  although  blocks  of  over 
a  ton  of  the  pure  sulpliide  have  been  taken  out. 

The  formation  of  these  ore  bodies  is  a  very  obscure  question. 
The  writer  in  1887  applied  to  them  the  views  that  had  been 
earl}'  advanced  by  Whitney  for  the  gash  veins  of  the  Upper 
Mississippi,  namely,  tiiat  decaying  marine  vegetation  had  pre- 
cipitated the  sulphides  from  sea  water.  This  is  very  doubtful, 
as  traces  of  algje,  or  any  other  fossils,  are  extremely  rare. 
W.  P.  Jenney  in  181).')  referred  them  to  solutions  uprising  along 


/-/•;. I />  A/.o.\h'. 


831 


uestitin. 

i  Upper 
Kul  pi'e- 
oubtful, 
;ly  rare. 
ug  along 


fault»<,  wliich  were  thoiiglit  to  cMit  the  oro  bodios,  aud  from 
wliicb  tlie  niinerali/iiij^  vvatci'H  had  spn'ad  laterally  through 
the  poroiiH  hetlH.  The  fault  at  Mine  la  Motte  along  which  the 
()!()  occurs  liMH  Ihhmi  earlier  cited  as  giving  Home  BUpjxwt  to 
thin  view,  altliough  rigiit  at  the  fault  the  ore  hodien  tend  to 
grow  lean.  Klsowliere  faults  are  insignilicant  so  far  as  known. 
Wiuslow  favors  the  desceut  of  solutions  from  above,  and  thinks 
tliiit  the  sulpbiiles  have  beeu  supplied  by  the  weathering  of 
overlyiug  strata,  now  in  largo  part  removed.  These  regions 
iiiive  been  liind  since  the  early  Carboniferous  times,  and  the 
HUperHcial  decay  has  been  enormous.  Lead-bearing  solutioris, 
it  ii^  thought,  have  filtered  downward  through  the  joints,  faults 
and  small  cracks,  and  have  deposited  their  dissolved  materials 
i)V  replacement  of  the  limestone.  The  conduits  seem,  how- 
over,  insignificant  when  compared  with  the  ore  bodies,  and  it 
is  evident  that  all  he  explanations  thus  far  suggested  involve 
(lilVu'ulfies. 

lu  the  Mississippi  Valley  in  this  portion  of  the  country  the 
Lower  Carboniferous  and  earlier  rocks  contain  lead  over  an 
area  of  more  than  15, 000  stjuare  miles.  Aside  from  these  dis- 
seminated ores,  zinc  is  always  associated  with  the  lead;  but 
iu  southeastern  Miss()Uri  it  is  practically  unknown  in  the  de])Os- 
its  of  the  disseminated  type.  There  are,  however,  iu  the  neigh- 
boring districts  several  mines,  such  as  the  Valle,  which  are 
closely  analogous  to  the  gash  veins  later  described,  and  which 
do  contain  zincblende.  The  history  of  Mine  la  Motte  dates 
back  to  the  early  part  of  the  eighteenth  century,  when  this 
ro^ion  figured  largely  in  John  Law's  Mississi])i)i  bubble.  The 
miiio  is  said  to  have  furnished  lead  for  bullets  during  the  war 
of  t.'ie  Revolution.* 


'  A  l)il)li()Krai)hy  of  the  lead  and  ziia;  regions  of  Missouri,  by  Arthur 
\Vin~ii)\v,  will  be  found  in  the  Reports  of  th^  Mifoiouri  Gcol.  Surivi/,  VII., 
I':iil  II..  |).  74'$.  It  conies  down  to  1H!(4.  A  l)ihlii>jj^rji|)hy  of  ]\riss()nri 
^^ciiln^'y  in  general  was  i)rei)ared  bj'  F.  A.  Sanii)soM  and  issued  as  linlUlin 
■  of  llir  Mo.  Geoi.  Survey,  in  1890.  A  revised  edition  by  ('.  R.  Keyes 
iippcaiN  iu  Vol.  X.,  of  t\w.  Siirreif,  p.  221,  and  conies  down  to  1S!)(5.  The 
"lore  iiu|)ortant  or  the  more  reciMit  i»ai)eis  are  given  below:  G.  C.  Broiid- 
Iieud.  The  Southeastern  Missouri  Lead  District."  TraiiH.  Ainer.  Inst.  M'ln. 
t'iH].,\..  100.  Rec.  J.  R.  (iage,  •  Occurrence  of  Lead  Ores  in  :Mis.souri," 
J(tem.  Ill  .  IKi;  also  (U'ol  Snrrcn  af  Mi.s.'<oiiri,  1S7;',-T4,  p]).  :!(),  (KKJ.  W.  P. 
Jeniiey,  •  Tlie  Lead  and  Zinc  nejtosits  of  the  Mississippi  Valley,"  Irans. 
An  a:  Iiixf.  Mill.  Kikj..  XXII.,  171,  (>3l,  1S93.     J.  F.  Kemp,  "Notes  on  the 


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232  KEMP'S  ORE  DEPOSITS. 

2.05. 1(/.  The  great  increase  in  lead  production  in  the  United 
States  came  about  1880,  with  the  opening  of  the  Leadville  ore 
bodies.  From  1877  until  1881  Eureka,  Nev.,  was  an  important 
source,  but  since  then  it  has  greatly  declined.  Utah  has  pre- 
served a  fairly  uniform  production  pince  the  early  seventies. 
Lead  from  all  sources  is  here  mentioned,  although  lead- 
silver  ores  are  subsequently  treated.  The  amounts  are  in 
tons  of  2,000  pounds.  For  detailed  statistics  see  the  annual 
volume  on  The  Mineral  Industry  (New  York:  Scientific 
Publishing  Company)  and  the  Annual  Reports  o^  the  Director 
of  the  U.  S.  Geological  Survey.  The  figures  for  l^lH!  are 
taken  from  the  Eighteenth  Annual  Report,  Part  V.,  p,  240. 

1880.  ISiin.  IH'.Ki. 

Missouri,  Kansas,  AVisconsin.  Illinois 27,()!)0  r)5,()()()  r)l.HS7 

Colorado 35,()74  (iO.OOO  44,M(l:! 

Nevada KMi-TiO  3,500  l.lT.i 

Utah 15,000  24,000  S.-i.oIS 

Jdalio.  Jlontana 24,000  57,r:W 

Elsewhere 2.802  lo.'JW  (),:i23 

97,82.")  181,494  197.491) 

From  80  to  8.5%  of  the  total  product  is  from  lead-silver  ores. 

Ore  Deposits,  etc.,  of  Southeastern  Missouri,"  <S(7ir>oi  o/JI/mt's  Quart  rly, 
October,  1887,74;  Ai)ril,  1888,  212.  C.  K.  Kcycs,  "The  Mine  la  :\l(>lt(> 
Sheet,"  Gi'ol.  Sio-vrj/  of  Miss<»iri,  IX..  Re)K)it  4.  1890.  A.  Litton,  Scnnid 
Ann.  Rep.  of  the  Firnt  Geol.  Survey  of  Mo.,  12-()4,  1854.  James  E.  Jlilis, 
Report  on  the  Minela Motte  Estate,  New  York.  1877.  H.  S.  IMuuroe.  •  Tlie 
New  Dressing  Works  of  the  St.  Joseph  Lead  Co.,  at  Bonne  Tene,  Mo.." 
Tram.  Amer.  lii.st.  Miu.Eiuj..  XVII.,  ().■)!»,  1HH8.  J.  W.  Neill,  "Notes  on 
the  Treatment  of  Nickel-Cobalt  Mattes  at  Aline  la  Motte,"  7f /('<(/,  XllI  . 
634.  F.  Posepny.  "On  Aline  la  Alotte."  (iciiesi.^  of  Ore  D<7>n.s//.s'.  )). 
107;  Trans.  Anwr.  Lint.  Miu.  Encj.,  XXTII.,  ;!(«,  1893.  H.  A.  WlieeltT. 
"On  Southea.st  Missouri  Lead  Alines.  Tlie  Cotlienj  Engineer,  18!l2.  ('. 
P.  AVilliams,  "Industrial  Kt'i)oit  on  Lead.  YAnv  and  Iron  in  Aliss.)uri," 
Jefferson  Cit\',  1877.  Arthur  Wiuslow,  "  Lead  and  Zinc  Deposits  of 
Alissouri,"  2  vols.,  Misaonri  Geol.  Survey,  \ll.,  Parts  I.  and  II.,  1894. 
A  very  complete  book  on  lead  and  zinc  in  {jjeneral.  Fairly  complete  libli 
o^raphy.  Part  II.,  j).  743.  A  fidler  one  by  F.  A.  Sampson  will  be  found  in 
Bulletin  J  of  the  Mo.  Geol.  Surrey,  1890.  Arthur  Winslow.  •Leadniiil 
Zinc  Deposits  of  Alissouri,  '  Trans.  Amer.  Inst.  Min.  Entj.,  XXIV..  f!:!!, 
931,  1894.  "Notes  on  the  Lead  and  Zinc  Deposits  of  tiie  Alississijjpi  Valley 
and  the  Origin  of  the  Ores."  Jour.  Geol.,  L,  012,  1893.  -Report  on  the 
Iron  Mountain  Sheet,"  Mo.  Geol.  Survey,  IX.,  Report  3,  p.  32.  relates  to 
Doe  Run.  "The  Disseminated  Tiead  Ores  of  Southeastern  Alisscnu'i,"  /?"' 
tetin  J.L>,  U.  S.  Geol.  Survey,  1890.  Rec.  The  best  brief  account,  His 
torical  Sketch  of  Lead  and  Zinc,"  Eny.  and  Min.  Jour.,  November  17,  21. 
1894;  January  19,  1895. 


Mills, 

••The 

Mo.." 

; oil's  on 

xiii.. 

I.S'//.S',      P 

Vheeli'V. 
IS'.IS.    ('. 
i>s>iuii. ' 
M)sits  of 
isiit. 
■U'  I'ilili- 
|'()\in<l  ill 
,c:nl  iiinl 
IV..  f.lU. 
pi  Viilli'V 
■t  on  tlu' 
rt'latrs  t(i 

iiri."  /?"'• 
lit.  -llis 


CHAPTER  VI. 

LEAD      AND      ZINC. 

2.06.01.  Example  24.  The  Upper  Mississippi  Valley. 
Gash  veins  and  horizontal  cavities  (Hats),  principally  in  the 
Galena  and  Trenton  limestones  of  the  Upper  Mississippi  Val- 
ley, and  containing  galena,  zincblende,  and  pyrite  (or  marca- 
site),  v/ith  calcite,  barite,  and  residual  clay.  The  deposits  are 
found  in  southwest  Wisconsin,  eastern  Iowa,  and  northwestern 
Illiuoia.  The  greater  portion  of  the  productive  territory  lies  in 
Wisconsin,  and  covers  an  area  which  would  be  included  in  a 
circle  of  sixty  miles  radius,  whose  limits  would  pass  a  few 
miles  into  Illinois  and  Iowa.  A  low  north  and  south  geanti- 
cline runs  through  central  Wisconsin,  dating  back  to  Arche- 
au  times  and  called  by  Chamberlin  "Wisconsin  Island." 
( )n  its  western  slope  the  Cambrian  and  Lower  Silurian  rocks 
are  laid  down,  and  these  in  the  western  limit  of  the  lead  dis- 
trict pass  in  the  adjoining  States  under  the  Upper  Silurian. 
They  are  folded  also  in  low  east  and  west  folds,  but  in  the  aggre- 
gate the  whole  series  dips  very  gradually  westward.  The  chief 
east  and  west  fold  forms  the  south  bank  of  the  Wisconsin 
River,  and  may  have  been  the  cause  that  deflected  it  from  a 
soutiierly  coxuse.  The  easterly  part  of  the  lead  region  is  ;5/)() 
feet  higher  than  the  western,  and  the  northern  is  500  feet  above 
tlie  sdiithern.     Tiie  general  slope  is  thus  southwesterly. 

2.(l().02.  The  Galena  limestone  is  a  dolomite  reaching  2r)()  feet 
in  thickness.  On  the  hilltops  left  by  erosion  Macjuekota  (Hud- 
son ]\iv<!r)  shales  are  seen.  The  Galena  has  shaly  streaks, 
which  liave  largely  furnished  the  residual  clay  of  the  cavities. 
Thero  are  also  cherty  layers  and  sandy  spots.  Under  the  Ga- 
lena lies  the  Trenton,  from  40  to  K'O  feet  thick,  and  made  up 
of  an  uj){)er  blue  portion,  which  is  a  pure  carbonate  of  lime, 


I  ■;    :M 


23  i 


KEMP'S  ORE  DEPOSITS. 


I 


and  a  lower  buflf  portion  that  is  magnesian.  The  upper  portion 
of  the  blue  has  a  baud  of  shale  locall}-  called  the  *'  Upper  Pipe 
Clay,"  and  the  pure,  cryptocrystalline  limestone  under  tliis  is 
called  "Glass  Rock."  The  blue  contains  much  bituminous 
matter.  The  buff  is  locally  called  "Quarry  Rock,"  and  is 
proliHc  in  fossils.  Under  the  Trenton  lies  the  St.  Peter's  sand- 
vtone,  loO  feet  below  which  is  the  Lower  Magnesian  (Oneota), 
100  to  '250  feet,  and  still  lower  the  Potsdam,  averaging  7i)0  to 
SOO  feet.  The  Potsdam  rests  on  the  quartzites  and  schists  of 
the  Archeau.    The  ore  bodies  especially  favor  the  shallow,  syn- 


FlG.  76. — (utxii.  cciim,  frexk  and  disuitegrnted.     The  heavy  black  shading  m 
dicates gaicna.     After  T.-  C.  Chamberliii,  OeoL  Win.,  Vol.  VF.,  454. 

clinal  depressions  of  the  east  and  west  folds.  They  occur  in 
crevices,  the  great  majority  of  which  run  east  and  west.  The 
productive  ground  comes  in  spots,  which  are  separated  1)}' 
stretches  of  barren  ground.  The  lead  ores  are  chiefly  produced 
by  the  crevices  in  the  Upper  Galena.  In  the  Lower  Galeua 
the  zinc  ores  become  relatively  more  abundant,  and  they  are 
also  in  the  Trenton.  The  ores  do  not  extend  in  any  apprecia- 
ble amounts  either  above  or  below  these  horizons.  The  upper 
deposits  favor  the  vertical  gash  vein  form ;  the  lower  tend 
rather  to  horizontal  openings,  called  flats,  which  at  the  ends 


LEAD  AND  ZINC. 


2;}5 


(lip  down  (pitches)  aud  often  connect  with  a  second  sheet  (flat) 
lying  lower.  There  are  several  minor  varieties  of  those  two 
main  types  of  cavity,  which  mainly  depend  for  their  differences 
on  the  grade  of  decomposition,  which  the  walls  have  under- 
gone, and  whether  there  was  an  original  opening,  or  only  a 
brecciated  and  crushed  strip.  Chamberlin  cites  twelve  varie- 
ties in  -^,11,  some  of  which  are  based  on  rather  fine  distinctions. 
A.  G.  Leonard  has  described  a  sheet  of  galena,  at  the  Lansing 
mine,  in  Iowa,  that  was  three  to  four  inches  thick,  'lb  to  ;}5  feet 
high,  and  over  1,000  feet  long.  Some  of  the  Iowa  crevices  have 
proved  remarkably  persistent  on  the  strike.  H.  F.  Bain  has 
called  the  writer's  attention  to  the  Lansing  mine  in  Allamakee, 
Iowa,  which  has  yielded  lead  ore  without  any  zinc  whatever, 


^  i»a-,\\\\\ 


SS:T-r  e  ni;gi^m-e^|Sta^ 


FlQ.  77. — Idi'ftlizi'il  section  of  '•  f,itK  and  pitc/ics,"  forms  of  ore  hodien  in  Wis- 
consin.    After  T.  C.  Vlinniberlin,  (ievl.  Wis.,  Vol.  IV.,  4r)8. 

aud  which  in  peculiar  in  that  it  occurs  in  the  Oneota  or  Lower 
^lagnesian  limestone,  aud  is  therefore  below  the  main  product- 
ive horizon  of  the  gash  veins.  The  crevice  also  trends  north 
and  south  as  against  the  usual  east  and  west  strike  of  the  gash 
veins. 

'-i.Ofl.OS.  The  cavities  were  referred  by  J.  D.  Whitney  to 
joints,  formed  either  b}-  the  dryiiig  and  consolidating  of  the 
lock,  or  by  gentle  oscillations  of  the  inclosing  beds.  The  later 
work  has  largelj'  corroborated  this,  and  they  are  generalh' 
thought  to  be  chiefly  caused  by  the  cracks  and  partings  formed 
by  the  gentle  synclinal  foldings.  Such  cavities  have  usually 
been  enlarged  by  subse(iuent  alteration  of  the  walls.     Whitney 


230 


A' EM  PS  ORE  DEPOHITS. 


alHO  essentially  outlined  the  explanation  of  origin,  which  has 
been  more  fully  elaborated  by  Chamberl'n.  Both  these  writ- 
ers have  urged  that  the  ores  could  not  have  come  from  below, 
for  the  lower  rocks  are  substantially  barren  of  them.  Tlie  con- 
clusion therefore  follows  that  they  were  deposited  in  the  lime- 
stones at  the  time  of  their  formation.  The  source  of  the  ores 
is  placed  in  the  early  Silurian  sea,  from  which  it  is  thought  they 
were  precipitated  by  sulphuretted  hydrogen,  exhaled  by  decay- 
ing seaweeds,  or  similar  dead  organisms  on  the  bottom.  In 
carrying  the  idea  further,  Chamberlin  has  ei.deavored  to  re- 
produce the  topography  of  the  region  in  the  Lower  Silurian 
times  and  to  indicate  the  probabhi  oceanic  currents.  These  are 
conceived  to  have  made  an  eddy  in  the  lead  district,  and  to 
have  collected  there  masses  of  seaweed,  etc.,  resembling  tlio 
Sargasso  Sea.  While  interesting,  this  must  be  considered 
very  hypothetical.  When  the  sulphides  became  precipitati'd 
they  were  doubtless  finely  disseminated  in  the  rock,  and  were 
gradually  segregated  in  the  crevices.  The  sulphurous  exhala- 
tions from  the  bituminous  limestones  may  have  aided  in  tli(  ir 
second  precipitation.  W.  P.  Jenney  in  181»;}  referred  the 
east  and  west  fissures,  mentioned  above  as  crevices,  to  faults, 
which  are  as  a  rule  not  far  from  the  vertical,  but  may  dip  '.\'° 
to  40°.  The  smaller  north  and  south  series  are  considered  to  lie 
likewise  due  to  faulting,  but  to  be  earlier,  as  they  are  thrown 
by  the  east  and  west  set.  The  displacement  fiom  the  latter  is 
horizontal  rather  than  vertical.  The  intersections  of  the  two 
sets  are  said  to  be  especially  favorable  to  ore  bodies.  Tlie 
name  "run"  is  applied  to  the  ore  body,  it  having  been  adopted 
from  southwest  Missouri.  The  ore  is  thought  to  have  been 
deposited  along  the  fault  fissures  bj-  uprising  solutions,  whicli 
have  spread  laterally  into  those  beds,  that,  from  their  chemical 
composition  (being  dolomitic)  or  their  open  structure,  were  fa- 
vorable to  them. 

In  the  same  year  (181);)),  W'.  P.  Blake  discussed  these  ore 
bodies,  paying  a  tribute  to  Percival's  early  views  on  faulting 
as  a  cause  of  the  veins,  and  describing  its  obscuritj'  and  the 
difficulty  of  demonstrating  its  presence.  Blake,  however,  cited 
the  Helena  mine  near  Shullsburg  as  an  instance  in  which  the 
mineralization  did  occur  near  a  pair  of  faults.  Blake  also  lays 
stress  upon  the    presence   of  thin   seams   of  rich  bitumiuous 


LEAD  AND  ZINC. 


237 


shale,  in  layers  usually  about  as  thick  as  cardboard,  which 
occur  in  a  richly  fossil  if  erous  limestone  at  the  top  of  the 
Trenton,  just  beneath  the  ore-bearing  "Galena"  dolomite,  and 
which  are  regarded  as  very  probable  factors  in  the  precipita- 
tion of  the  ore. 

The  mining  region,  it  should  be  emphasized,  lies  within  the 
peculiar,  unglaciated  area,  which  is  one  of  the  notable  geologi- 
cal features  of  this  por+ion  of  the  country.  It  has,  therefore, 
long  been  exposed  to  the  atmospheric  agents,  and  has  not  been 
denuded  of  the  residual  products  of  decay  as  have  the  glaciated 
districts. 

The  papers  of  Jenney  and  Blake  led  to  a  notable  discussion 
of  these  ore  bodies,  and  to  wide  divergence  of  views  regarding 
tliem.  Arthur  Winslow,  in  connection  with  his  more  extended 
treatment  of  those  in  Missouri,  has  urged  that  the  sulphides 
have  been  supplied  from  the  overlying  strata,  during  the  exten- 
sive, subaerial  decay  to  which  these  have  been  subjected.  Pass- 
ing ini'o  solution  the}'  are  thought  to  have  percolated  into  the 
crevices  and  to  have  been  precipitated.  A.  G.  Leonard,  in  his 
•study  of  the  Iowa  veins,  reaches  a  similar  conclusion,  but  on 
account  of  the  impermeability  of  the  Matjuekota  shales,  restricts 
the  source  of  the  ore  to  theOalena  dolomite.  The  frecjuent 
occurrence  of  the  ores  in  stalactites  projecting  downward  from 
the  roof  of  a  chamber  gives  support  to  these  views.  Leonard 
favors  Chamberlin's  view  of  the  precipitation  from  a  sup- 
posed Sargasso  Sea  of  the  Ordovican  times. 

The  paragenesis  of  the  minerals  shows  the  following  suc- 
cession: (1)  Pyrite,  {'>)  Galena,  (:})  Pj^rite;  or  (1)  Pyrite,  (2) 
Blende,  (:5)  Galena,  (4)  Pyrite;  or  (4)  Calcite.  The  ores,  espe- 
cially of  zinc,  are  often  oxidized,  and  afford  considerable  cala- 
mine and  smithsonite.  Some  oxidized  copper  ores  are  produced 
at  Mineral  Point,  formed  by  the  alteration  of  chalco pyrite.  In 
tlie  tarly  mines  lead  alone  was  sought,  but  of  late  years  the 
zine  has  been  produced  in  greater  quantities,  and  is  more  valu- 
able than  the  lead.'  Smithsonite  is  fomid  in  commercial  quan- 
tities as  well  as  blende. 

'  Wisconsin.— J.  A.  Allen,  "Description  of  Fossil  Bones  of  Wolf  and 
Deer  from  Lead  Veins.",  Amer.  Jour.  Sei.,  iii.,  II.,  47.  VV.  P.  Blake,  -The 
Mineral  Deposits  of  Southwe.st  Wisconsin,"  Trans.  Amer.  Inst.  3lin. 
£'",'/.,  XXn.,  .'ins,  iHOa     Uec.     Amer.   Geol.,  XII.,  237,   1S93.     "  The  Ex- 


rl 


238 


Kh'MI'S  OBJ!:  DFA'OSITS. 


2.0G.04.  Example  'Z\a.  Washington  County,  Missouri. 
Gash  veins  in  the  Potosi  cherty  limestone  of  eastern  Missouri 
in  the  same  region  as  the  disseminated  ores  of  Example  2;i,  and 
containing  galena,  barite  (locally  called  "tiff"),  calcite,  and 
residual  clay.  The  cavities  are  described  by  Whitney  as  re- 
sembling in  all  respects  the  gash  veins  further  north,  which, 
however,  lie  in  rocks  higher  in  the  geological  ries.  These 
mines  were  the  earliest  worked,  but  have  been  given  up  since  the 


istence  of  Faults  and  Dislocations  in  the  Lead  and  Zinc  Regions  of  the 
Mississi))))!  Valley,  with  Observations  uiH)n  the  Genesis  of  the  Ores,"  Idem, 
()21.  Kec.  This  last  paper  was  written  in  discussion  of  one  hy  VV.  P. 
Jenney,  cited  below.  "  Wisconsin  liCad  and  Zinc  l)ei)osits,"  Bull.  Ucol. 
Soc.  Amer.,  V.,  35,  1893.  "Progress  of  Geological  Survej's  in  the  State  of 
Wisconsin — a  Review  and  a  Bibliography,"  Trims.  Wis.  Acad.  Sci.,  IX.. 
22'i.  T.  C.  Clianiberlin,  U7,s.  r/co/.  SKrvcy,  IV.,  IHH3,  p.  3«7.  Rcc. 
K.  Daniels,  "Geology  of  the  Lejid  Mines  of  Wisconsin,"  Auicr.  Asso,  Adr. 
Sci.,  VII.,  2\){);  Wis.  Gcol.  Survey,  IH'A-  E)iq.  and  Min.  Jour.,  July  6,  i:{, 
20,  37,  Augu.st  8,  10,  34,  October;"),  1HT8,  Icceniber  14,  1SS9,  533.  James 
Hall,  "Notes  on  the  Geology  of  the  Western  States,"  Amer.  Jour.  Sci.,  i., 
XLIL,  51.  W.  H.  Hobbs,  "A  Contribution  to  tlie  Mineralogy  of  Wiscon- 
sin." Hull.  Unir.of  Wis.,  Science  Series  I.,  114;  see  i\\no  Zeitseli.  fi\r  Kri/sf.. 
XXV.,  35T,  1895.  J.  T.  Hodge,  "On  tlie  Wisconsin  and  IMissouri  Le;i(l 
Region,"  Amer.  Jour.  Sci.,  i.,  XLIII.,  ;{5.  R.  D.  Irving,  "  Mineral  Re- 
sources of  Wisconsin,"  Trans.  Amer.  In.^t.  Min.  Euy..  VIII.,  4TS.  E. 
James,  "Remarks  on  the  Limestones  of  the  Mississippi  Vallej'  Lead 
Mines,"  Piiila.  Acad.  Sci.,  V.,  Part  I.,  p.  51.  W.  P.  Jenney,  "The  Lead 
and  Zinc  Depo.sitsof  the  Mississippi  Valley,"  Trans.  Amer.  Inst.  Min.  Ku;).. 
XXII.,  171,  (i31,  1893.  Rec.  J.  Murrish,  Report  on  the  Lead  Regions. 
1871.  as  commissioner  for  their  survey.  D.  D.  Owen,  "Re]M)rt  on  tlie  Lead 
Regi<m,"  U.  S.  Senate  Docmnents,  1844.  J.  G.  Percival,  Wis.  Geol.  Sur- 
veij,  185fi.  Squier  and  Davi.s,  "  Historical  Account,"  .S»((7/i.sY)H/o/(  Contri 
bufions.  Vol.  I.,  p.  208.  M.  Strong,  Wis.  (Jeol.  Survey,  1877,  I.,  ();i7;  II., 
(i45,  089.  J.  D.  Whitney,  Wis.  Oeol.  Survey,  1861-03,  I.,  321.  Rec.  Mv- 
taJlic  WeidtlK  p.  403,  IM.IO.  "On  the  Occurrence  of  Bones  am' Teeth  in 
the  Lead- bearing  C Crevices,"  Amer.  Assoc.  Adv.  Sci.,  1859.  Arthur  Win.s 
low,  "Lead  and  Zinc  Deposits  of  Missouri,"  Trans.  Amer.  Inst.  Min.  Emj.. 
XXIV..  es])ecially  677-690,  1894.  See  also  Vol.  VI.  of  Geol.  Purvey  of 
Mo.,  135-150,  1894. 

Illinois. — J.  Shaw,  Geol.  Survey  of  Illinois,  1873,  II.,  340.  J.  1' 
Whitney,  Idem,  1866,  I.,  153. 

Iowa. — A.  G.  Leonard.  "Lead  and  Zinc  Deposits  of  Iowa."  loiva  Geol 
Survey,  VI.,  1896.  Rec.  "Origin  of  the  Iowa  Lead  and  Zinc  Deposits," 
Amer.  Geol,  XVI.,  288,  1895;  Eng.  and  Mia.  Jour.,  June  37,  18!)6,  (il4; 
Colliery  Engineer,  XVII.,  131,  1896.  C.  A.  White,  Iowa  Geol.  Survey.  1870. 
II.,  p.  i339.     J.  D.  Whitney,  Idem,  1858,  I.,  p.  433. 


LEAD  AND  ZINC. 


239 


price  of  lead  has  been  at  present  figures  (1875  and  subse- 
(juently).  The  ore  was  obtained  from  pockets,  caves,  irregular 
cavities,  and  from  the  overlying  residual  clays.  This  whole 
ref^ion  has  been  exposed  and  above  water  since  the  close  of 
Carboniferous  times,  and  has  suffered  enormous  surface  decay 
(seeR,  Pumpelly,  Tenth  Census,  Vol.  XV.,  p.  12,  and  iieol. 
Soc.  Anter.,  Vol.  II.,  p.  20),  which  has  left  a  mantle  of  residual 
clay  spread  widely  over  its  extent.  In  this,  more  or  less  Hoat 
niiueral  occurred.  The  mines  were  located  in  Washington, 
Franklin,  Jetfnrsou  and  St.  Francois  counties.'  Very  similar 
deposits  in  rocks  of  about  the  same  geological  horizon  also 
occur  in  the  central  part  of  the  State,  in  tbe  counties  near  the 
Osage  River.  The  district  has  been  called  the  Central  by 
Winslow. 

2.(i(i.05.  Example  24&.  Livingston  County,  Kentucky. 
Veins  in  limestone  of  the  St.  Louis  stage  of  the  Lower  Carbon- 
iferous, contfiining  galena  in  a  gangue  of  Huorite,  calcite  and 
clay.  The  ore  bodies  have  never  been  well  described,  antl  no 
very  accurate  account  can  be  given.  They  are  found  in  Liv 
ingstou,  Crittenden,  and  Caldwell  counties,  Kentucky ,  in  that 
portion  of  the  State  lying  south  of  the  Ohio  River  and  east  of 
the  Cumberland.  While  limestone  always  forms  one  wall,  a 
sandstone  of  geological  relations  not  well  determined  forms  the 
other.  The  veins  run  from  two  to  seven  feet  wide  and  in  in- 
stances are  richer  in  their  upper  portions  than  in  the  lower. 
As  yet  they  are  of  greater  scientific  than  practical  importance. 
Some  galena  occurs  also  in  irregular  cracks  in  the  limestone. 
As  a  possible  indication  of  a  stimulating  cause  for  the  forma- 
tion of  the  veins,  the  interesting  dike  of  mica-jjeridotite  may 
be  cited,  which  has  been  described  by  J.  S.  Diller."  The  dike 
occurs  in  the  same  fissure  with  a  vein  of  fluorspar. •' 

'  Comiiare  the  older  references  under  Example  23,  and  the  following: 
A.  l-iUi)n,  Second  Ann.  Rep.  Mi.sHonri  Geol.  Surrey,  1854.  J.  D.  Whitney, 
MihilUc  Wealth,  p.  419.  Artliur  Wiiislow,  "Lead  and  Zinc  Deposits  of 
Missouri,'  Vols.  VI.  and  VII.  of  Mu.  Geol.  Survey;  Trann.  Amer.  Inst. 
Min.  J-:,,!,.,  XXIV.,  cm. 

"    '^lic-aPeridotite  from  Kentucky,"  Amer.  Jour.  Sci.,  October,  1893. 

'  S.  V.  Enunous,  'Fluorspar  Deposits  of  Southern  Illinois,"  Trans. 
Aiiitr.  lust.  Min.  Eng.,  February,  1893.  C.  J.  Norwood,  "ReiHn-t  on  the 
Li'iid  K'ciiinn  of  Livingston,  Crittenden  and  Caldwell  Counties,"  Ken- 
tiirl.-y  a,;,!.  Survey,  1875,  New  Series,  Vol.  I.,  p.  449. 


340 


KEMPS  QUE  DEPOSITS. 


m 


3.(HJ.00.  Example  '^5.  Southwest  Missouri.  Ziiicblende 
and  very  subordinate  galena  with  their  oxidized  ijroducts,  hhso- 
ciated  with  chert,  residual  clay,  calcite,  a  little  pyrite  and  l)ilu- 
nien,  in  cavities  of  irregular  shape  and  in  shattered  portions  of 
Suhcarboniferous  limestone.  Across  Missouri,  from  a  point 
south  of  St.  Louis,  and  including  the  country  as  far  to  the 
northwest  as  Sedalia  and  Glasgow,  a  broad  belt,  called  the 
Ozark  uplift,  extends  southwesterly  into  Arkansas.  It  has 
formed  a  great  plateau  in  central  and  southern  Missouri,  and 
consists  largely  of  Silurian  rocks.  These  have  a  fringe  of 
Devonian  on  the  edges  and  dip  under  the  Lower  Carboniferous. 
Tlie  plateau  reaches  1,500  feet  above  the  sea  in  Wright  County, 
but  on  the  limit  is  succeeded  by  lower  country.  To  tlio 
southwest  it  drops  somewhat,  with  Lower  Carboniferous  strata 
outcropping,  which  in  Kansas  are  overlain  by  the  coal  measures. 
The  surface  then  rises  again  in  the  prairies.  At  the  edge  of 
the  plateau  is  a  trough,  in  whose  bottom  the  Lower  Carbonifer- 
ous strata  are  cut  by  the  Spring  River,  which  flows  southwest- 
erly from  Missouri  across  the  western  State  line  into  Kansas, 
and  has  a  general  direction  parallel  to  the  western  limits  of  tlie 
uplift.  Tt  receives  tributary  streams  on  each  bank,  which  cut 
the  strata  in  strongly  marked  valleys,  and  afford  good  ex{)0- 
sures.  Those  on  the  east  bank,  from  south  to  north,  are  Slioal 
Creek,  Short  Creek,  Turkey  Creek  and  Center  Creek,  while 
from  the  west  come  the  Brush,  Shawnee,  and  Cow  creeks,  all 
in  Kansas.  Along  the  first  m«^ntioned  creeks  the  principal 
mining  towns  are  situated,  but  others  are  found  on  the  minor 
streams.  They  extend  through  an  area  fifteen  miles  broad 
from  east  to  west,  and  twenty-five  miles  from  north  to  south. 
Newton  and  Jasper  are  the  most  productive  counties  in  Mis- 
souri, while  Cherokee  County,  in  Kansas,  also  contains  nota- 
ble mines.  Undeveloped  districts  are  recorded  in  Arkansas, 
but  apparently  at  a  low^er  geological  horizon.  The  ore  occurs  in 
the  Keokuk  or  Archimedes  limestone  of  the  Lower  Carbonif- 
erous. A  generalized  section  of  the  rocks,  according  to  F.  L. 
Clerc,  is  as  follows :  On  ^,ne  higher  prairie,  some  15  feet  of 
clay  or  gravel;  10  feet  'n  Hint  or  chert  beds;  40  feet  of  lime- 
stone with  thin  beds  oi  chert;  (JO  feet  of  alternating  layers  of 
limestone  and  cher*-;  KtO  feet  and  more  of  chert,  sometimes 
chalk^^  with  occasional  beds  of  limestone;  325  feet  in  total.    In 


LKAn  AM)  ZINC. 


Ul 


basins  and  extensive  pockets  in  these  rooks,  deponita  of  slates 
with  Hnmll  coal  seams  are  found,  t)f  undetermined  geological 
miations.  The  large  bed  of  limestone  of  the  section  affords  a 
datum  of  reference  in  relation  to  which  the  ores  may  be  de- 


_8%rounil  Ore  . 


_S2«_ 


r.% 


34% 


i  a 


No  Ore 


NoOro 


.  T5%FounJ  «0  to  80  ft.Lena  A  ZInf 
KO'i(iFoiin<l 


No  Ore 


No  Ore 


gO'liJFound  Ore 


No  Ore 


^  JO%Fguml_Z I  nr  Pro  »t  1075  to  1100  ft. 


If     '^    t^     ■if 


NoOrp. 


No  Ore 


I    t 


Tlio  Flint  and  Limestone  anmo  as  nt  the  surface. 


Tig.  78. — Chart  showing  the  rcsi/Ux  of  die  p  boriugx  in  the  Joplin  district.  Mo. 
From  the  KiKjiaeering  and  Mining  Journal,  March  18,  18i)9,  p.  321. 

scribed.  A  few  minor,  shallow  deposits  occur  in  the  flints  over 
it.  lu  the  limestone  the  ores  are  associated  with  a  gangue  of 
(lolomitic  clay  and  residual  flint.  They  occupy  irregular  cavi- 
ties or  openings,  locallj'  known  as  circles,  spar  openings,  and 


M'^ 


243 


KNMP'S  OliK  DEPOSITS. 


ruiJH.  (Clorc. )  Below  tli(«  liiruwtone  the  ore  is  foiiiid  in 
"nlioetH,  baiidw,  HoaniH,  and  pcK'kets,"  Hn<l  filling  in  the  inter- 
stices of  a  bre(^cia  of  chert,  which  liaH  been  formed  hy  the 
brcakiiip^  down  of  the  chert  layers  on  the  sointiojis  and  removal 
of  tho  interl)('dd(>d  limestones.  TluMe  are  distric^ts  wiien^  th(» 
overlyiuj^  bed  of  lin^eston<>  lias  also  disjiiipefirec'  and  they  then 
lack  it  for  a  cappinj^.  The  deposits  extend  considerable 
de{)ths  below  the  position  of  the  limestone.  The  present  mines 
have  not  demonstrated  as  yet  their  limit  of  depth.  At  times 
the  ore  is  associated  with  a  later-formed  (piartz  rock  that  has 
coated  and  filled  the  cavities  of  the  breccia. 

Althoiijj;h  the  mininj^  is,  as  yet,  comparatively  shallow,  llir 
results  of  a  large  number  of  deep  bore-holes  are  now  available, 
and  are  shown  in  the  accompanying  Fig.  7H.  From  the  chart 
it  is  evident  that  there  are  four  ore-bearing  horizons  distributed 
down  to  a  depth  of  about  f,l(H)  feet.  Below  this,  and  down  to 
3, (»(>')  feet,  no  ore  was  met.  The  holes  were  all  drilled  in  Jas- 
per County,  and  near  Joplin  and  Webb  City. 

2. ()•'». 07.  The  removal  of  the  interbedded  layers  of  limestone 
and  the  caving  in  of  the  associateil  "herts  have  been  the  j)rinf'i- 
pal  causeis  of  the  formation  of  cavities.  Adolph  Schmidt  re- 
ferred the  shrinkage  to  the  dolomitization  of  pure  lime  carbon- 
ate, an  idea  that  has  had  extended  adoption.  J)olomitiza1it)ii 
has  also  an  important  part  in  causing  the  general  porosity. 
Schmidt  traced  five  periods  in  the  geological  history  of  the  ore 
bodies:  1.  Period  of  deposition  of  the  rocks,  'i.  Period  of 
dolomitization  of  certain  strata  and  of  principal  ore  deposition. 

3.  Period  of  dissolution  of  part  of  the  limestone,  of  brfakiii^' 
down  of  chert,  and  of  continued  but  diminishing  ore  deposition. 

4.  Period  of  regeneration,  secondary  deposition  of  carbouate  of 
lime  and  quartz,  and  continued  ore  deposition.  5.  Period  of 
oxidation. 

Schmidt's  work  was  done  in  1871-72.  Since  then  the  in- 
creased development  of  the  mines  has  afforded  greater  opportu- 
nities for  observation.  Haworth,  in  18is  1,  referred,  with  nnicli 
reason,  the  shattering  of  the  chert  in  >'^ertain  areas  to  oscilla- 
tions of  the  strata,  and  Clerc,  in  18.S7,  emphasized  particularly 
the  dissolving  action  of  water.  It  is  a  iiard  problem  to  dis- 
cover the  original  source  of  the  metals.  The  earlier  writers 
said  nothing  of  this  subject,  or  else,  as  in  Haworth's  paper,  (lis- 


IKAJJ  AND  ZINC. 


243 


lul    in 

intt>r- 
ly  the 
moval 
»ro  tho 
y  then 
lerahle 

mincH 
t  tinios 
liat  has 

ovv,  the 
rtilablc, 
le  chart 
tvihuti'd 
Jown  to 
1  in  Jiis- 

tnestone 
e  princi- 
luidt  ro- 
)  cavlion- 
itizalion 
ponwity. 
t'  the  ore 


lliifal 
positic 


ho 


aate  of 


cussed  a  possible  precipitation  from  tlie  ocean,  or,  as  in  Clerc's, 
referred  thoin  to  the  pockots  of  slate  and  coal.  In  is'.t;{,  at  tho 
Chicago  nieotinj^  oi  the  American  Institute  of  Mininj^  Engi- 
neers, W.  P.  Jonney  presented  an  abstract  of  the  results  of  his 
work  wiiile  detailed  by  the  U.  S.  Geological  Survey  to  study 
these  ore  deposits.  As  will  appear  in  the  abstract  of  the  paper 
given  beU)\v,  the  ores  are  supposed  to  bavo  come  up  through 
fissures  of  displacement,  and  bouce  from  below.     These  con- 


■    ■   ■   ,    ■   /  :    •    ■■;,•'  \'    •     •      •     ,/•■••/,•.■•'/■'•    .■  /       Probable  flint  floor  of 
Typical  zinc-blende  ohe-bod*  near  Wedb  City,  Mo.   Vehtioal  Section. 


Subcarboniferous  Limestone 

in 

&  Flint  rook 


^r'yi,^^  Flint  rocK 


™  '^^Zinc-blonde ore-bodlf 


Worked  out  part  ol* 
oro-depoait. 


'eri 


•—^. — ^k..    Qalanite  in  fissures  &  bodding-planos  in  llmestona 
Fig.  79. — Vcvfirnl  si-rtiou  of  a  typical  ziiwhh  itde  ore  hodj/,  near  Wibh  (My, 
.\fo.     Ajtev  C.  Ifcnrieh,  Trifnn.  Ainer.  Inst.  Miii.  liny.,  XX.,  p.  \\. 


|o 


elusions  have  been  controverted  by  others,  on  account  of  the 
(lirticulty  in  proving  the  existence  of  faults  when  evidence  of 
(lisphioement  is  so  obscure.  In  Jenney's  paper  all  the  lead  or 
lead  and  zinc  regions  of  the  Mississippi  Valley  are  considered 
together.  They  are  described  as  occurring  along  three  lines 
of  uplieaval.  The  region  of  Wisconsin  and  Iowa  is  on  the 
tiauks  of  the  Archean  "Wisconsin  Island"  of  Chamberlin,  re- 
ferred to  above  under  2.0().01.     The  southeast  and  southwest 


244 


KEMP'S  ORE  DEPOSITS. 


t 


Missouri  regions  are  on  the  Ozark  uplift,  while  a  minor  argen- 
tiferous galena  district  is  on  the  line  of  the  Ouachita  uplift  of 
Arkansas  and  Indian  Territory.    The  formation  of  the  ore  bod- 
ies in  the  first  three  of  these  is  regarded  as  having  been  in  gen- 
eral the  same.     They  are  thought  to  have  originated  from  up- 
rising solutions,  which  came  through  certain  principal  fissures. 
and  spread  laterally  into  strata  favorable  to  precipitation.     In 
southwest  Missouri   this  was  the  Cherokee  limestone  of  the 
Lower  Carboniferous.    In  its  unaltered  state  it  is  an  extremely 
pure  carbonate  of  lime.     It  has  a  maximum  fcliickness,  where 
not  eroded,  of  105  to  200  feet,  and  contains   many  intcrbedded 
laj'ers  of  chert.     Much  organic  matter,  and  more  or  less  bitu- 
men, are  also  at  times  present.     The  limestone  seems  to  have 
been  raised  above  the  ocean  level  at  the  close  of  the  Lower 
Carboniferous,  and  to  have  remained  for  a  long  period  exposed 
to  the  atinos[)heric  agents.     Much   caving  in  of  unsuj)porte(l 
layers  of  chert  and  much  attendant  brecciation  resulted.     Tbe 
general    stratum   became  (luite  open  and  cellular  in   certaiu 
portions.     At  a  later  period,  supposed  from  several  indications 
to  be  at  the  close  of  the  Cretaceous,  dynamic  disturbance  oc- 
curred, which  along  certain  lines  produced  fissures,  sometimes 
parallel,  sometimes  intersecting.     Solutions  arose  through  tliese 
which  dolomitized  much  of  the  remaining  limestone  and  caused 
additional  porositj'.     Zinc    and   lead   ores  were  afforded,  ;uid 
where  the  conditions  were  favorable  they  spread  laterally  from 
the  fissures  and  deposited  the  sulphides  in  the  cellular  rock  or 
replaced  the  limestone  itself.     The   intersection  of  crossing  tis- 
surrs  is  a   fre(|uent  point  of  deposition,  and  at  times  parallel 
master  fissures  have  given  a  wide  area  of  impregnation.     This 
form  of  ore   deposit  is  called  a  run.     The  ri;ns  are  from  5  to  50 
feet  in  height,  100  to  300  feet  long,  and   10  to  50  feet  across. 
At  Webb  City  thej'  are  even   larger.     As  a  general  thing  tbe 
ore  '.A  in  the  interstices  of  the  brecciated  chert,  but  it  is  also  in 
limestone  and  dolomite,  and  associated  with  a  silicified  form  of 
the   insoluble  residue   left   by  the   solution   of  the   limestoue, 
which  Jeunoy  calls  "chorokite. "     All   the   ores  require  oou- 
centration.      Galena   usually   occurs  near   the  surface,    while 
blende  is  more  abundant  in  depth.      Ctidniium  is  at  times  pres- 
ent in  the  blende  in  notable  amount. 
In  181)-1,  the  ver)'  thorough  report  of  Arthur  Winslow  on  lead 


^-■-"■^'^"•^^-"-'-'^ 


LEAD  AND  ZINC. 


245 


ami  zinc  in  Missouri,  and  incidentally  elsewhere  in  the  world, 
appeared,  and  likewise  a  briefer  account  before  tbe  American 
Institute  of  Mining  Engineers.     Winslow  gives   in   the  large 
volumes  the  most  detailed  work  of  reference  yet  issued,  and 
reaches  a  quite  different  view  regarding  the  derivation  and  for- 
mation of  the  ores.    He  emphasizes  the  fact  that  the  region  has 
long  been  a  land  area,  in  fact,  ever  since  the  close  of  the  Lower 
Carboniferous  times.     The  subaerial   decay  has  therefore  been 
excessive  and  a  considerable   thickness  of  overlying  rock  has 
goue.     This  has  favored  the  formation  of  caves,  sinks  and  un- 
derground waterways,  which  have  often  collaj^sed.    Extremely 
careful  analyses  of  fresh  and  large  samples  of  the  various  lime- 
stones a^JSociated  with  or  overlying  tbe  lead  and  zinc  deposits 
of  the  State  were  made,  as  well  as  of  a  series  of  the  Archean 
rocks,  from  which,  in  the  course  of  long  erosion,  the   others 
are  supposed  to  have  been  derived.     The  Archean  rocks  j'ielded 
U.oor.i"  to  O.UOOS  per  cent,  lead  (.04   to  .j;3(;   pounds  per  ton), 
and  {).(I01;51»  to  0.0170  per  cent,  zinc  (.028  to  .352  pounds  per 
ton);  the  Silurian  Magnesian  limestones,  a  trace  to  0.00150  per 
cent,  lead  (up  to  .O;}   pounds  per  ton);  and  a  trace  to  0.015;38 
percent,  zinc  (up  to  .oOT  pounds  per  ton);  the  Lower  Carbon- 
iferous limestones,  a  trace  to  O.OicUO  per  cent,  load  (up  to  .07 
pounds  per  ton),  and  a  trace  to   0.002r)(;   per  cent,  zinc  (up  to 
.0."i  pounds  per  ton).     Winslow  concludes  from  the  above  data 
and  observations  and  from  the  difficulty,  if  not  impossibility, 
of  discovering  actual  evidence  of  fault  fissures,  that  the  orew 
have  become  concentrated  in  the  shattered  rock  by  the   down- 
ward percolations  of  lead  and  zinc-bearing  solutions,    which 
have  derived  the  metals  from  the  overlying  and  largely  decom- 
posed strata. 

2.00.08.  Some  interesting  alterations  of  the  minerals  have 
oeourrod,  which  have  changed  the  blende  to  smithsonite  and 
calamine.  Li  one  case  a  secondary  precipitation  of  zinc  sul- 
phide has  yielded  a  white,  amorphous  powder,  which  is  of  very 
recent  date.  With  the  original  precipitation  of  the  blende,  the 
asphaltic  material  may  have  had  something  to  do.  In  the 
matter  of  production,  W.  P.  Jenney  fixes  the  ratios  of  the 
blende,  galena,  and  pyrite  at  about  1,000  :  80  :  O.5.' 

'  Missouri. — G.  C.  Broadhead,  "Geological  History  of  the  Ozark  Up- 
lift." Amcr.  Geoi,  III.,  C.     II.  M.  Chance,   "The  Rush  Creek   (Arkansas) 


246 


KEMP'S  ORE  DEPOSITS. 


2.00.00.  Other  zinc  and  lead  deposits  are  known  in  cential 
Missouri  generally  resembling  the  above  quite  strongly,  but 
of  less  economic  importance.  Some,  however,  are  described 
by  Schmidt  as  conical  stockworks.  They  sometimes  are  fouLd 
in  Lower  Silurian  strata. 


rig.  s. 


ENLARGED   SECTION    SHOWING    RELATION    OF   ZINC-ORE 
TO   THE    LIMESTONES   AND   CLAY. 


Fro.  80. — Qeologicnl  section  of  the  Bertha  zine  mines,  Wythe  County,  Vn. 
After   W.  11.   (',t.t'-,  Tr<(n.t.   .\mer.   fN.st.    Miii.    Eng.,  XXII.,  p.  r>i\). 

2.00,10.     Both  the  mines  of  Example  2r)  and  those  of  Exam- 
ple 24  v.'ere  originally  worked  for  lead,  and  the  zinc  minerals 

Zino  District,"  Trnuft.  Amcr.  Imt.  Min.  Eng.,  Vol.  XVIII.,  p.  mn.  IH'.Kl. 
F.  L.  Clere,  f  Jeol<)<2;ical  description  of  the  iniiies  in  a  statistical  painplilct 
on  the  Lead  tnid  Zinc  Ores  of  Soiithire.'it  .l//.s.s'«*//'/  .l/.'y/cs',  p.  4,  piihlislit'd 
by  J.  M.  Wilson,  Cartilage,  l\Io.,  1HS7.  Rec.  See  also  Eng.  and  Min. 
Jour.,  June 4,  1887,  p.  ;?{)T;  "Zinc  in  tlie Ignited  Stiites,"  Mincnil  Rc.soiircis. 
1H82,  p.  t3()8.  G.  T.  Cooley,  "Dressing  Lead  and  Zinc  Ores  in  Kansas." 
Eng.  and  Min.  Jour.,  July  7,  189.">,  p.  !).  Eng.  and  Min.  Jour.,  November 
:i  1H8S.  ],.  ;]8!):  :Marcli  s.  IS'.KI.  p.  '.JSC..  "  Distribution  of  Lead  and  Zinc  near 
.Toplin.  Mo.."  litem.  .March  IS.  18!)L  WU.  Kec,  L.  llaworth,  "  A  Contribu- 
tion to  the  Geology  of  tlie  Lead  and  Zinc  Jlining  District  of  Cherokee 
County,  Kansas,  Oskaloosji.  Iowa."  1884.  C.  Henrich,  "  Zincblende  Mines 
and  Mining  near  Webb  City,  Mo.,"  Trann.  Awer.  In.sf.  ^^in.  Eng.,  XXI., 
p.  ;},  1892;  Eng.  and  Min.  Jour..  June  4,  181)2.  J.  R.  Ilolibiuigli,  "The 
Lead  and  Zinc  Mining  Industry  of  Soutlnvest  Missouri  and  Southeast  Kan 
siis,"  Eng.  and  Min.  Jonr..  LVIIL,  18(14.  llfO.  ;{!)4,  4i:i.  4:!7.  4(i0.  48.-,,  ,-,0S  and 
.');5.1i.  Also  issued  as  a  separate  book  by  the  Scientific  Publishing  Co  .  •">" 
(lents.  W.  P.  Jenney.  "Lead  and  Zinc Dei)osits of  the  Mississippi  Valley." 
Trans.  Amcr.  Inst.  Min.  Eng.,  XXII.,  171,  18!«.     Rec.     C.  Luedekinj,^aii<l 


LEAD  AND  ZINC. 


247 


ceutial 
ly,  but 
scribed 
3  fouLd 


ntji,  Vfi. 
.).  520. 

)f  Exam- 
miuevals 


Avere  regarded  as  a  nuisance ;  of  late  years  the  zinc  bas  been 
nuicb  more  of  an  object  than  the  lead.  The  deposits  in  south- 
west Virginia  (Example  2(i)  also  produce  lead,  but  are  best 
known  for  zinc. 

2.0G.11.  Example  20.  Wythe  County,  Va.  Residual  de- 
posits or  crusts  of  calamine  and  smithsonite,  resting  upon 
Lower  Silurian  (Ordovician)  limestone  or  dolomite,  and  prob- 
ably  derived  from  disseminated  blende,  during  the  weathering 
of  the  country  rock.  Deposits  of  blende  are  also  known  in  the 
limestone.  The  ore-bearing  terrane  is  exposed  over  a  considera- 
t)le  extent  of  country,  running  from  near  Roanoke,  one  hundred 
miles  westward.  The  largest  mines  are  in  Wythe  County,  and 
of  these  the  Bertha  is  best  known.     The  Bertha  ores  are  cala- 


M.  A.  Wlieeler,  "Notes  on  Missouri  Bariti',''  Aiiicr.  Jour.  ScL,  Dei-ember, 
isid,  p.  495.  R.  W.  Riiyniond,  "Note  ou  the  Ziuc  Deposits  of  Southern 
Missouri,"  Tnints  Amcr.  lii.st.  Mil).  Eng.,  VIII.,  Ifi.");  Eihj.  (tiiil  Miii.  Jour., 
October  4,  bST'J.  J.  D.  Robertson,  "  X  New  Variety  of  Zinc  Suipliide  from 
llicrokee  County,  Kansiis,"  Amer.  Jour.  Sci.,  iii.,  XL.,  p.  KiO.  "Missouri 
i.ead  and  Zinc  DejMj.sit.s,"  Aiiwr.  Geol.,  April,  ISU."),  S;}").  A.  Sclimidt  and 
-V.  Leoiiliard,  jlis.wiiri  Geol.  Survey,  1874  A.  Sflimidt,  "Forms  and 
(Jri;.^in  of  tlie  Ijead  and  Zinc  Deposits  of  Southwest  Missouri,"  'Traii.s.  St. 
I.iiui.^  Acad.  ScL,  III.,  24(5;  Auicr.  Jour.  ScL,  iii.,  X.,  l^.  ;?<»().  Die  Blciiind 
Ziiik  ErzliKjcr.'^fdttoi  rou  Siiduw.sf  J//.s.so(//7',  Ileidell)erj^,  Ciermauy,  ISTfi. 
K.  J.  S(!lunitz,  "Notes  of  a  Reconnaissance  from  Sprinj;lield,  Mo.,  into 
Aricausas,"  Troii.^.  Aincr.  Inst.  Min.  Emj.,  February,  1898.  W.  H.  Sea- 
iiuin,  "Zinciferous  Chiys  of  Southwest  Jlissouri,"  Auwr.  Jour.  ScL,  iii., 
XXXIX.,  p.  ;5H.  H.  S.  Wiclis,  "The  Joplin  District,"  Entjiuecriny  Moij- 
iizuie.  February,  1H!)4.  Arthur  \Vinsk)w,  "  Notes  on  the  Lead  and  Zinc 
l)e])()sits  of  the  Mississii)pi  Valley  and  the  Origin  of  the  Ores,"  Jf>»/-.  of 
f ''(')/..  I.,  (U2,  lS!);i  Rec.  "Lead  and  Zinc  Dei)Osits  of  Missouri,"  Trons. 
.\iiicr.  lunt.  Miu.  Eug.,  XXIV.,  084  antlDiU.  Rec.  "Report  on  Lead  and 
Ziiii-,  '  Mi,ssouri  Geol.  Surrci/,  VI.  and  VII.,  1894.  Rec.  See  also  pamphlet 
oil  ••Misi-(mri  at  the  World's  Fair,"  189;{.  "Historical  Sketcii  of  Lead  and 
/.inc,"  Euy.  and  Min.  Jour.,  November  17,  24,  1894 ;  .January  19,  1895. 

K.\xsAS. — G.  P.  (jrinisley,  "Kansas  Mineral  Products,"  Eleventh  Bien- 
iiiitl  Report  Kiiii.sos  Board  <if  Ai/ricnltiire.  1897-9S,  .502.  E.  llaworlh.  "A 
Contribution  to  the  tJeology  of  tiie  Lead  and  Zinc  Mining  District  of 
Cherokee  County,  Kan.,  Oskaloosa,  la.,"  1894,  privately  printed.  R.  Hay, 
"(Jt'oionical  jind  ^Mineral  Pesources  of  Kansas."  Eighth  liieuuial  Report 
Sl(de  llnurd  of  Agriculture,  1891-92,  25.  B.  F  Mudge,  Jdeui,  ls78.  O. 
Ht.  John,  hleni,  1881-82.     See  also  J.  D.  Robertson,  cited  vuider  Jlissouri. 

.\i!K.v.NsAS. — E.J.  Schmitz,  "Notes  of  a  Reconnaissance  from  Spring- 
ticltl.  Mo.,  iuto  Arkansas."  Trans.  Auicr.  lunt.  Miu.  Eng.,  February,  1898. 
.V  Report  ou  Lead  and  Zinc  in  Arkansjis  is  now  iu  press  with  the  St(de 
deol.  Sun-eij  (1899). 


248 


KEMP'S  ORE  DEPOSITS. 


mine  and  sniithsonite,  both 
crystallized  and  earthy  or 
ochreous.  Tliey  lie  upon 
a  limestone  which  is  of 
very  irregular  surface,  be- 
ing so  deeply  pitted  by 
superficial  decay  that  it 
projects  in  knobs  and  pil- 
lars, and  sinks  in  interven- 
ing depressions.  These  are 
shown  very  graphically  in 
Figs.  82  and  813,  where 
they  are  left  in  relief  by 
tbe  stripping.  They  arn 
mantled  and  rounded  oil' 
by  the  overlying  residual 
clay,  which  may  be  60  to 
75  feet  deep.  The  ore  lies 
in  crusts  and  chunks  or  as 
a  powdery  mass  upon  or 
near  the  limestone  in  the 
clay,  and  is  won  either  by 
stripping  this,  or  by  shafts 
and  drifts.  (See  Fig.  80.) 
According  to  Boyd,  in  one 
section  there  are  48G  feet 
of  strata  impregnated  with 
zinc  and  lead  sulphides,  . 
with  some  pyrite.  At  the 
Wythe  Company's  mines 
both  the  oxidized  ores  and 
tbe  unchanged  sulphides 
of  zinc  and  lead  in  tlie 
underlying  limestone  are 
exploited,  but  at  the  Ber- 
tha mines  there  is  practi- 
cally no  lead,  the  product 
being  a  very  pure  speller. 
More  or  less  limonite    is 


NIVlNnONtllVd  ONIUVOH 


eSNIN-SNIZ  VHllJ3a 
II3AIU  M3N 


tN\ 


tXltVA  HJbno 


s> 


11<«i 


NiviNnoM  uadvtio 


•«  -tl  •»  V  -H 


n'^vd 


linM 


a 


£   f  3 


a  ' 

2  , 


:  :9  fl  ^  i 


i-l  S  -I 


o:s  Bi2  art 


:r   ;*    3   fl    <3  o 


loom 


e 
I 


ft) 


5» 


K 
.« 


taNiw-ivos  «Nooiiy 


liii 


Fig,  82. — View  of  open  cut  in  the  Bertha  Zinc  Mines,  Va.    From  a 
photograph  by  J.  F.  Kemp,  1895. 


Fig,  83. — View  of  open  cut  in  the  Wythe  Zinc  Mines,  Va.    From  a 
photograph  by  J.  F.  Kemp,  1895. 


I' 


Wit 


J 


* 

! 

'i 

; 

i 

i; 

r 

LEAD  AND  ZING. 


249 


obtained  from  all  these  surface  workings,  and  is  sent  to  neigh- 
boring blast  furnaces. 

Near  Bonsacks  the  gossan  of  the  ore  was  exposed,  but  not 
recognized  for  a  long  time,  in  a  cut  of  the  Norfolk  and  Western 
R.  R.  The  mine  yielded  rich  earthy  oxidized  ores,  which,  how- 
ever, passed  in  dopth  into  a  very  intimate  and  rebellious  mix- 
ture of  zinc-blende  and  pyrite.  These  deposits  extend  over  a 
wide  stretch  of  country,  running  from  near  Roanoke,  one 
hundred  miles  westward/ 

Related  deposits  occur  in  eastern  Tennessee,  and  have  fur- 
nished more  or  less  ore,  chiefly  calamine.  They  are  not  large 
as  a  rule.''  They  occur  in  the  Knox  dolomite,  at  the  base  of 
the  Lower  Silurian,  and  favor  its  contact  with  the  underlying 
Cambrian  Conasauga  shale^  in  the  area  of  the  Cleveland  folio 
cited  below. 

'LOli.r^.  Blende  is  a  frequent  associate  of  galena  in  the 
Rocky  Mountains,  but  it  has  been  only  recently  worked  for 
any  zinc  product,  and  then  largely  as  a  by-product  in  extract- 
ing silver.     (See  2.07.10.) 

'  C.  R.  Boyd,  "Resources  of  Southwest  Virginia,"  p.  71.  "Mineral 
Wealth  of  Southwest  Virginia,"  Trails.  Amei:  Inst.  Mhi.  Eng.,  V.,  81; 
Tbid.,  Vlll.,  340.  "  The  Wythe  Lead  and  Zinc  Mines,  Va.,"  Eng.  and  Min. 
Jour.,  June  17  and  24,  1893.  W.  H.  Case,  "The  Bertha  Zinc  Mines  at 
Itertha,  Va.,"  Trans.  Amer.  Inst.  Min.  Eng.,  Vol.  XXII.,  p.  511,  August, 
1H9;5.  H.  Credner,  Zeitsch.  fvr  die  gesammten  NatHrnuHsenschaften,  1870, 
XXXIV.,  p.  24.  F.  P.  Dewey,  "Note  on  the  Falling  Cliflf  Zinc  Mine 
(Bertha  Company),"  Trans.  Amer.  Inst.  Min.  Eng.,  X.,  Ill,  A.  v. 
(iidildeok,  Tifpus  Austin.  Lehre  von  den  Lagersliltten  der  Erze,  p.  103. 

'  J.  M.  Salford,  Genlogif  of  Tennessee,  p.  482.  W.  H.  Gildersleeve, 
"  Zinc  Ores  in  Tennessee, "  University  Scientific  Magazine,  August,  1896. 
Quoted  by  the  Eng.  and  Min.  Jour.,  September  18,  1897,  336. 

'  Cleveland  Folio,  by  C.  W.  Hayes.  U.  S.  Geol.  Survey,  Morristown 
Folio,    Arthur  Keith,  Idem, 


CHAPTER  VII. 


vmt 


ZINC  ALONE,  OR  WITH  METALS  OTHER  THAN  LEAD. 

2.07.01.  Zinc  commonly  occurs  in  association  with  lead, 
but  there  are  one  or  two  exceptional  deposits  in  this  country 
which  are  without  lead,  and  which  have  no  parallel  in  other 
parts  of  the  world.  The  minerals  containing  zinc  at  Franklin 
Furnace  and  Ogdensburg,  N.  J.,  are  known  elsewhere  only  as 
rarities,  although  they  are  found  in  vast  amounts  in  New 
Jersey.^ 

ZINO  SERIES. 

Zn.       S. 

Sphalerite  (commonly  call  blende)  ZnS 67        33 

Zincite,  ZnO 80. 3 

Franklinite,  (Fe.Zn.Mn)0(Fe.Mn)a03 (variable)    5.54 
Willemite,  2ZnO.SiO, 58.5 


Fe.      SiO, 


'a- 


SZnO.SiOa,  HaO. 


54.2 


Calamine, 

Smithsonite,  ZnO.COg 52. 0 


51.8 


27 
25 


Mu. 


7.i) 


2.07.03.  Example  27.  Saucon  Valley,  Pennsylvania. 
Zinc-blende  and  its  oxidation  products,  calamine  and  smith 
sonite,  filling  innumerable  cracks  and  fissures  in  a  disturbed, 
magnesian  limestone,  thought  to  belong  to  the  Chazy  stage. 
The  ore  bodies  occur  in  the  Saucon  Valley  near  the  town  of 
Friedensville,  about  four  miles  south  of  Bethlehem.  The  lime- 
stone is  inclosed  between  two  northerly  spurs  of  the  Soutli 
Mountain,  and  has  apparently  been  tilted  and  shattered  by 
the  upheaval  of  the  latter.  The  shattering  and  disturbances 
decrease  as  the  South  Mountain  is  left  and  the  dip  decreases. 
There  are  three  principal  mines,  the  Ueberroth,  the  Hartmau, 
and  the  Saucon,  the  first  named  being  in  the  portion  which  is 

'  F.  L.  Clerc,  "Zinc  in  the  United  States,"  Mineral  Resources,  1882,  p. 
358.  W.  R.  Ingalls,  "  The  Nomenclature  of  Zinc  Ores,"  Trans.  Amer.  Inst. 
Min.  Eng.,  XXV.,  17  and  955,  1895. 


ZINC  ALONE. 


251 


Ivama. 
sinitb- 

^turbed, 

Y  stage. 

town  of 
e  lime- 
South 
red   by 
rbances 
creases, 
artmau, 
hich  is 

|s,l883,  p. 
\mer.  i"''*^- 


tilted  nearly  to  a  vertical  dip,  and  is  much  disturbed,  while 
the  next  is  where  the  dip  has  gradually  decreased  to  '^b°.  The 
mines  are  on  a  belt  some  three-cjuarters  of  a  mile  long.  At  the 
Ueberroth  an  enormous  quantity  of  calamine  was  found  on  the 
surface,  but  it  passed  in  depth  into  blende  and  was  clearly  an 
oxidation  product.  In  the  others  the  blende  came  nearer  the 
surface.  The  ore  follows  the  bedding  planes,  and  the  joints 
normal  to  these  throughout  a  zone  varying  from  10  to  40  feet 
across,  and  fills  the  cracks.  At  their  intersection  the  largest 
masses  are  found.  Six  larger  parallel  fissures  were  especially 
marked  at  the  Ueberroth.  This  mine  proved  in  development 
to  be  very  wet,  and  a  famous  pumping  engine,  the  largest  of 
its  daj',  was  built  to  keep  it  dry.  The  Hartman  and  Saucon 
are  less  wet.  A  little  pyrite  occurs  with  the  blende,  and  thin, 
powdery  coatings  of  greenockite  sometimes  appear  on  its  sur- 
face, but  it  is  entirely  free  from  lead  and  a  very  high  grade  of 
spelter  is  made  from  it.  The  mines  were  strong  producers 
from  185;3  to  187(),  but  little  has  been  done  since,  although  it  has 
been  reported  that  the  great  pumping  engine  might  again  start, 
and  the  mines  may  once  more  furnish  considerable  quantities  of 
ore. 

3.07.03.  The  veins  were  evidently  filled  by  circulations  from 
below  that  brought  the  zinc  ore  to  its  present  resting  place  in 
the  shattered  and  broken  belt.  Drinker  considers  it  to  have 
been  derived  from  a  disseminated  condition  in  the  limestone.' 

2.07.04.  Example  28.  Franklin  Furnace  and  Sterling, 
N,  J,  Bed  veins  consisting  of  franklinite,  willemite,  zincite, 
etc.,  in  crystalline  limestone,  in  many  respects  analogous  to  the 
magnetite  of  Example  13.  The  franklinite  and  zincite  bedded 
deposits  are  in  a  belt  of  white,  crj'stalline  limestone  which  runs 
southwesterly  from  Orange  County,  New  York,  across  north- 
western New  Jersey.  It  was  cofcsidered  metamorphosed  Lower 
Silurian  by  H.  D.  Rogers,  but  its  association  with  Archean 
gneiss  is  so  intimate  and  involved  that  others  have  regarded  it 
as  likewise  Archean.     Blue   Siluro-Cambrian    limestone  and 

'  F.  L.  Clerc,  Mineral  Renourees,  1882,  361.  Rec.  H.  S.  Drinker,  "On 
tlie  Mines  and  Works  of  the  Lehigh  Zinc  Company,"  Trann.  Avier.  Iiiftt. 
Mill.  Eng.,  I.,  67.  C.  E.  Hall,  in  Rep.  DU.  Second  Geol.  Survey,  Penn.,  p. 
2H!).  Die  Griiben  und  Werke  der  Lehigh  Zink  Oesellschaft  in  Pennsyl- 
vunien,  B.  und  H.  Zeit.,  1872,  p.  51. 


*■   -i 


-Z52 


KKMP'S  OHM  DMI'OSfTS. 


I'lii-^iwy    ,  ■'** ' 


(jimrtzite  are  hIho  near.  F.  L.  Nasou  has  recently  supported  the 
Canihro-Siluriau  age  of  the  white  limeHtone,  on  the  ground 
that  the  white  and  the  bhie  varietioH  are  inextricably  involved, 
and  that  many  intruwionH  of  granite  are  present,  which  would 
account  for  tiio  nietaniorphisni  of  the  latter.  In  one  of  the 
Hnialler  areas  of  blue  that  was  in  the  midst  of  the  white,  some 
fossils  of  the  Olenollus  fauna  were  discovered.  J.  E.  Wolff 
and  others  in  association  with  him  have  referred  the  white 
limestone  to  the  Archean  rocks,  and  have  agreed  that  the  blue 
was  either  mixed  with  it  because  of  faults  or  because  the 
quartzite  had  tilled  cavities  in  the  former  during  the  advance  of 
the  Cambrian  sediments  across  the  Archean  rocks.  Of  the 
presence,  however,  of  granites  and  other  intrusions  in  the  white 
limestone  there  is  no  doubt,  but  they  are  thought  by  Wolff  to 
be  pre- Cambrian,  and  probably  to  be  later  than  the  ore.  In 
limestones  and  ore  at  once  so  mashed  and  so  old  the  relations 


BUCKWHtAT 


Fig.    H4. — Crons   xcrtion.    at    Fnm/.liii    FitriKici',    N.    »/.,    corrcHponding    to 

AA.  of  map  (Fl({.  88),  aiuljui/r  tiiiirs  the  scale  of  map.      At  the  left 

is  blue  limestone  and  quartzite.     After  J.    F.    Kemp, 

Trans.  N.  Y.  Acad,  of  Sciences,  XIU.,  86,  1893. 

are  obscure.     At  Franklin  Furnace  the  crystalline  limestone 
forms  a  low    hill  (Mine  Hill)  east  of  the   upper  waters  of  tlio 
Wallkill,  and  again  at  Ogdensburg,  two  miles  south,  another 
(Sterling  Hill),  on  the  west  bank.  There  is  a  valley  and  unex- 
posed strip  between,  so  that  the  unbroken  continuity  without  a 
possible  intervening  fault  cannot  be  established.     The  bed  at 
Franklin  outcrops  on   the  west  side  of  the  hill.     It  begins  ou 
the  north  just  across  the  Hamburg  road,  and  runs  south  30° 
west  as  a  continuous  bed  for  about  2,500  feet.     This  portion  is 
called  the  Front  vein.     It  contains  on  the  north  the  old  Ham- 
burg mine,  then  the  Trotter  mine,  and  in  the  southern  portion 
belongs  to  the  New  Jersey  Zinc  and  Iron  Company.     It  runs 
from  8  to  30  feet  broad  at  the  outcrop,  but  swells  below.     It 
dips  southeast  40  to  <iO°  into  the  hill,  and  is  interbedded  in  the 
limestone.     In  the  Trotter  mine  a  wedge  or  horse  of  hornblende, 


the 
lund 
veil, 
ould 
'  the 
some 
VolfE 
A'liite 
)  blue 
le  the 
uce  of 
)£  the 
white 
olff  to 
•e.     Ill 
latiourt 


mestoiie 
s  of  tUo 
\iK)tber 
n\  uuex- 
thout  a 
bell  iit 
gins  oil 
i)iith  311' 
ortioii  is 
\(\  Ham- 
t  portion 
It  runs 
low.     It 
3d  in  tbe 
t-nblende, 


Fia.  85. — Vietv  of  the  xoest  vein  at  Franklin  Furnace  looking  south, 
two  shafts  are  at  the  Trotter  Mine.     Photograplied 
by  J.  F.  Kemp,  1893. 


The 


« 


MM 


Flo.  yO. —  Mew  of  opcnritt  at  south  end  of  Mine  Hill,  Fmiiklhi  Furnace, 

N.  J.,  exjjoniiiij  the  .si/neliiie  of  ore.     From  a  photoijraph 

hij  J.  F.  Kemp,  February  24.  1S90. 


^^.^   I^W^fK-^..    . 


Fia.  ^l.—View  of  Stirling  Hill,  Ogdendmrgh,  N.  J. ,  looking  southwent from 

the  N.  Y.,  S.  and  W.  R.  R.  embankment.     The  mines  arc  at  the 

foot  of  the  hill.     From  a  photograph  by 

J.  F.  Kemp,  1892. 


ZINC  ALONE. 


253 


aiigite,  plagioclaHO,  and  varit)iiH  other  Hi licateHenterH  the  \wA  a 
nbort  (listauce.     In  tliia  liorsH   wonie  of  the  niowt  intereHtin^ 
nnneralw  have  been  found,  wuch  aH  fluorite,  rhodonite,  blende 
(var.  cleiophane),  snialtite  (var.  cholantbite ),  axinite,  etc.    At 
tlio  end  of  the  Front  vein — or,  more  properly,  bed— a  braneh  or 
bend  atrikes  off  at  an  angle  of  :{()  to  40°  to  the  east.     'I'hiH  more 
easterly  bnuuih,  which  is  called  the  Buckwheat  mine,  outcrops 
on  the  surface  some  oOO  feet,  and  then,  after  being  cut   b}*  a 
traj)  dike  'I'l  feet  wide,  pitches   down  at  an  angle  of  *^7°  and 
passes  under  the  limestone.     The  jiortion  of  tla*  mine  northc^ast 
of  the  dike  furnishes  the  most  and  best  ore.     Tiie  surface  out- 
crop of  the  Buckwlieat  was  'i^^  to  150  feet  across,  but  it  swelled 
liclow  to  b'l  feet,  and   in  the  8econ<l  level,  about  aoo  feet  from 
the  surface,  it  was  penetrated    by  across-cut  ri5  feet  without 
finding  the  wall.     The  character  of  the  ore  varies;  for,  while 
it  is  excellent  at  the  point  of  the  cross-cut,  at  \'Zh  feet  nearer 
the  intersection  with  the  front  bed  it  becomes  lean,  wliile  pre- 
serving its  width  lower.     Beyond   the  dike  the  bed  is  likewise 
broad,  and  is  mined  out  for  40  to  hO  feet  across.    The  workings 
are  now  sonie  distance  down  on  the  pitch.     The  impression 
made  by  the  arch  of  the  roof  and  by  the  curving  beds  is  that 
this  is  tlie  crest  of  an  anticline  whose  axis  pitches  north  '27°, 
and  whose  central   portion   is  formed   l)y  the  franklinite  bed 
being  doubled  up  together  on  itself  before  the  two  parts  <li verge 
iu  depth.    Its  western  jwrtion  probably  is  continuous  in  a  syncli- 
nal trough  with  the  front  bed,  and  its  eastern  portion  dips  east 
at  some  miknown  angle.     It  may,  however,  be  merely  a  bulg- 
ing termination  of  the  bed  and  the  results  of  deeper  mining  will 
be  awaited  with  interest. 

About  181)0  deep  drilling  was  instituted  along  the  strike  of 
the  Buckwheat  ore,  and  about  one-third  of  a  mile  distant  from 
it.  The  holes  caught  the  ore  at  approximately  1,000  feet  down, 
ami  a  large  shaft  was  at  once  installed  which  has  since  proved 
extremely  productive.  The  workings  have  shown  tliat  the 
prulougation  of  the  Buckwheat  ore  body  flattens  notably  at  this 
portion,  and  rounds  out  along  the  strike  in  a  sort  of  spoon-bowl 
termination.  To  express  the  exact  shape  in  this  portion  the 
stereogram  Fig.  00  should  be  somewhat  modified,  still  it  illus- 
trates the  general  shape  fairly  well.  Apparently  the  ore  is  cut 
off  by  a  fault  to  the  northeast,  but  the  relations   are  not  yet 


254  KEMP'S  ORE  DEPOSITS. 

fully  demonstrated.  The  whole  southern  portion  of  the  ore 
body,  as  far  as  the  trap  dike,  is  now  being  stripped  of  limestone 
preparatory  to  open-cut  mining,  and  the  geological  relations 
are  beautifully  displayed. 

3.07.05.  The  ore  consists  of  franklinite  in  black  crystals, 
usually  rounded  and  irreguhu',  but  at  times  affording  a  quite 
jierfect  octahedron  combined  with  the  rhombic  dodecahedron 
and  set  in  a  matrix  of  zincite,  willemite  and  calcite.  The  rich- 
est ore  lacks  the  calcite  and  consists  of  tho  other  three  in  vary- 
ing proportions.  The  best  ore  is  in  largest  amoimt  in  the 
Buckwheat  mine,  beyond  the  trap  dike  which  cuts  it.  The 
limestone  containing  the  ore  has  a  notable  percentRo'e  of  man- 
ganese replacing  the  calciuin,  and  where  it  is  exposed  to  the 
atmosphere  it  weathers  a  characteristic  brown.  An  analysis 
of  a  sample  occurring  with  the  ore  at  Sterling  Hill  afforded 
F.   C.  Van  Dyck: 

CaCOj 80.23 

MnCO., 16. 57 

FCaOj 0.50 

SiOg 0.20 

HgO 1.00 

100.50 

The  percentage  of  manganese  is  very  high  for  a  limestone. 

2.07.00.  The  Sterling  Hill  outcrop  is  less  extensive.  It  be- 
gins on  the  north  with  the  New  Jersey  Zinc  and  Iron  Com- 
pany's property,  and  runs  south  ;{0°  west  for  ],100  feet.  It 
then  branches  or  bends  around  to  the  west  and  runs  north  00° 
west  for  ;50  feet,  bending  again  to  north  30°  east,  and  pitches 
beneath  the  surface.  Thus  the  general  relations  between  the 
front  and  back  beds  are  somewhat  the  same  as  at  Mine  Hill. 
and  the  dip  and  pitch  are  similar.  The  principal  working's 
are  on  the  Front  vein,  where  there  are  two  veins  (beds),  ac- 
cording to  the  older  descriptions,  one  rich  in  franklinite  ami 
the  other  in  zincite.  It  is  doubtful  if  there  really  are  two  dis- 
tinct beds,  but  probably  one  portion  is  richer  in  zincite  than 
the  other.  The  part  mined  is  from  two  to  ten  feet.  The  f<H)t- 
wall  is  corrugated  and  causes  many  pinches  and  swells,  wlin.se 
troughs  pitch  north.  The  limestone  between  the  front  and 
back  outcrop  is  charged  with  franklinite  and  various  silicates 


ZINC  ALONE. 


255 


(jeffersonite,  augite,  garnets,  etc.),  and  has  been  mined  out  in 
large  o])en  cuts  now  abandoned.  A  deposit  of  calamine  was 
found  in  the  interval  about  187*),  and  has  furnished  many  fine 
museum  specimens. 

2.07.07.  It  is  not  clear  that  the  Sterling  Hill  and  Mine  Hill 
deposits  were  once  continuous.  The  bed  at  Mine  Hill  runs  in 
the  front  portion  close  to  the  contact  of  the  white  limestone 
and  the  gneiss.  The  Sterling  Hill  bed  is  much  fartber  away 
from  tbe  gneiss,  and  this  would  indicate  that  it  is  at  a  higher 
horizon.  The  evidence,  too,  of  a  pitching  syncline  is  strong, 
but  a  pitching  S-fold  is  not  as  clear.  A  faulting  of  the  Arche- 
an  rocks  in  an  east  and  west  line  across  their  strike,  and  a  sub- 
sequent tilting  so  as  to  give  them  a  northerly  pitch,  is  a  very 


;one. 

Itbe- 
Coni- 
eet.     It 
n-tb  no° 

pitolii^;^ 
reen  tbe 
Qo  Hill. 

orkin^^s 

ds),  HC- 
ite  aiitl 
;\vo  dis- 
ite  tbau 
'he  foot- 
,^  whose 


FuirRES  S8  and  Hi). — Gcolof/ifal  mop.'^   of  Mine  Hill  and  tStcrliiu/   lliH, 

shoicin(/  tfic  nliitions  <\f  Vie  on-lnxliis.     After  J.   F.  Kemp, 

TriuiH.  N.    Y.  Acad,  of  Sciences,  Kill,, 

pp.  81  and  85,  ISftJ}. 

widespread  phenomenon  in  the  Highlands,  and  lends  weight 
iu  this  instance  to  the  idea  that  a  fault  intervenes  between  the 
two  bills. 

•-i. 07.08.  The  origiii  of  these  beds  is  very  obscure.  They 
are  so  unique  in  their  mineralogical  composition  that  verj'  lit- 
tle direct  aid  is  furnished  by  deposits  elsewhere.  At  Mine 
Hill,  below  tbe  franklinite  bed  a  bed  of  magnetite  was  early 
discovered,  and  was  mined  for  iron.  It  has  since  been  met  iu 
the  drill  cores  from  the  deep  shaft  of  the  northeast,  and  is 
therefore  remarkably  persistent  beneath  th  zinc  ore.  There 
are  many  points  of  analogy  between  tbe  franklinite  beds  and 
extended  magnetite   deposits.     They  are   both    minerals  of  the 


'will 


266 


KEMP'S  ORE  DEPOSITS. 


spinel  group,  and  the  spinels  are  a  common  result  of  metamor- 
phic  action.  The  presence  of  zincite  and  willemite  complicates 
matters,  however,  and  while  an  original  ferruginous  deposit 
might  be  conceived  with  a  large  percentage  of  manganese, 
such  abundance  of  zinc  is  beyond  previous  experience.  It 
is,  however,  suggestive  that  no  inconsiderable  amount  of  zinc 
is  found  in  the  Low  Moor  (Va.)  limonites,  as  shown  by  the 
flue  dust  (see  E.  C.  Means,  "The  Dust  of  the  Furnaces  at  Low 
Moor,  Va.,"  Buffalo  meeting,  Amer.  Inst.  Min.  Eng.,  XVIL, 
p.  17!)),  and  this  in  the  course  of  a  protracted  blast  may  amount 
to  many  tons,  but  it  does  not  approach  the  Franklin  Furnace 
ores.  None  the  less,  in  the  absence  of  a  better  explanation,  the 
franklinite  bed  may  he  tliought  of  as  perhaps  an  original  man- 


FlGURES  90  and  91. — Stereograms  of  the  ore  bodies  at  Mine  Hill  and 

Sterling  Hill.     After  J.   F.  Kemp,   Trans.  N.    Y.  Assoc. 

of  Sciences,  XIII.,  pp.  m  and  89,  1893. 

ganese,  zinc,  iron  deposit  in  limestone,  much  as  many  Siluro- 
Cambrian  limonite  beds  are  seen  to-day,  and  that  in  the  gen- 
eral metamorphism  of  the  region  it  became  changed  to  its  pres- 
ent condition.  Minerals  of  the  spinel  group  occur  all  througli 
this  limestone  belt,  J.nd  in  Orange  County,  New  York,  to  the 
north,  there  is  an  old  and  prolific  source  of  them. 

2.07.01).  As  has  been  earlier  stated,  granite  intrusions  are 
common  in  the  white  limestones  adjacent  to  or  near  the  ore, 
and  unless  these  are  proved  to  be  of  later  ago  than  the  ore,  they 
may  have  been  an  important  factor  in  the  ore  formation.  It 
is  very  reasonable  that  the  igneous  intrusion  should  start  ore- 
bearing  currents  along  a  certain  stratum  in  the  limestone, 
which  would    replace  it   with   ore.     Subsequent  folding  and 


wmmE^. 


ZINC  ALONE. 


257 


nietamorphism  must  then  have  changed  these  ores,  whatever 
they  were,  to  the  present  unusual  minerals. 

This  view  of  the  method  of  origin  has  been  advocated  by 
J.  F.  Kemp  in  the  paper  cited  below,  and  more  careful  search, 
as  well  as  the  sinking  of  the  new  shaft  on  the  strike  of  the 
back  vein  at  Mine  Hill,  have  served  to  bring  to  light  more 
intrusions  of  granite  than  were  previously  known.  Chon- 
drodite,  fluorite  and  other  contact  minerals  occur  near  them. 
Nason  has  also  shown  by  an  interesting  series  of  analyses  that 
the  limestone  next  the  granites  tends  to  be  pure  CaCOs,  shading 
gradually  at  a  distance  to  dolomitic  varieties.  Victor  Mon- 
heim,  in  discussing  the  vein  of  willemite  worked  in  the  forties 
at  Stolberg,  near  Aachen,  has  urged  that  at  temperatures  suffi- 
ciently high  the  anhydrous  silicate  of  zinc  may  separate  di- 
rectly from  the  solutions,  while  at  loAver  temperatures  the 
hydrous  salt  results.  His  experiments  and  conclusions  give 
support  to  the  view  that  the  igneous,  plutonic  intrusions  have 
jilayt'd  an  important  role  iit  the  ore  deposition.  (See  V.  Mon- 
lieira,  Verh.  d.  Naturhist  Ver.  der  preus.  Rheiulande  u. 
IVestphalen,  V.,  1G2, 1848;  VI.,  1,  184't.)  Were  this  true  we 
would  not  be  compelled  to  assume  an  original  bed  of  blende 
from  which  theso  oxidized  compounds  have  been  derived.  It 
is  a  general  experience,  however,  that  hydrated  oxidized  ores 
of  zinc  have  passed  in  depth  into  blende,  aud  this  fact,  in  con- 
nection with  the  almost  entire  absence  of  blende  in  these  mines, 
adds  to  their  puzzling  character.  Were  they,  however,  at  one 
time  a  thoroughly  oxidized  gossan  containing  the  three  metals 
specially  prominent,  the  intrusions  of  granite  are  probably 
responsible  for  the  change  to  their  present  combinations.' 


'  F.  Alger,  "On  the  Zinc  Mines  of  Franklin,  Sussex  Co.,  N.  J.,"  Amei'. 
Join:  Sci.,i..  XLVIII..  253,  1845.  Rec.  J.  Beco,  De  I'Etat  actual,  des 
Industries  du  Zinc,  etc.,  aux  Etats  Unis  d'Anierique,  Revue  Univei'scUe 
(Us  Mines,  1877,  11.,  129.  W.P.Blake,  in  paper  on  "Zinc  Ore  Deposits 
of  SoiitiiwesteniNew  Mexico,"  Trans.  Amer.  Inst.  Min.  Eng.,  XXIV.,  187, 
WH,  >;ives  notes  on  the  "  New  Jersey  Ore  Bodies."  N.  L.  Brittou,  Ann. 
lii'p.  of  the  State  Oeologist,  N.  J.,  1886,  p.  89.  An  excellent  cross-section 
if  Mino  [Till  is  pven.  (}.  H.  Cook,  "On  the  Probable  Age  of  the  White 
f-iniestoiie  at  the  Sussex  and  Franklin  Zinc  Mines,"  ^iincr.  Jour.  Sci.,  ii., 
XXXII.,  208.  Geol.  of  New  Jersey,  m^,  imn,  with  mai).  Rec.  II.  Cred- 
IHM-.  ■•On  the  Franklinite  Beds,"  Berg -n.  Ilntt.  Zeitnng.  180(5,  29;  1871, 
3Gl».     Rec.     E.  F.  Durre,   "  Metallurgische  Notizen  aus  New  Jersey  und 


ir'-fir 


258 


KEMP'S  ORE  DEPOSITS. 


2.07.10.  Blende  is  known  in  numerous  places  in  the  Rocky 
Mountains,  and  is  often  argentiferous.  When  mixed  with 
lead  silver  ores  it  has  generally  proved  a  drawback,  and  has 
raised  the  smelting  charges.  Recentlj'  works  have  been  erected 
at  Caiion  City,  Col.,  for  the  treatment  of  such  ores,  and  very 
considerable  quantities  of  blende  are  there  turned  into  zinc- 
white.  While  the  local  demand  for  this  pigment  is  not  so 
heavy  in  the  West  as  in  the  East,  any  process  which  frees  tho 

dd'ii  Leiiigli  Thill,"  Zeitseh.  des  Vereias  deiitscher  Itigenieare,  1894,  p.  184. 
B.  i'.  Emerson,    "On  the  Dykes  of  ^Micaceous  Diuhase,  Penetrating  the 
Bed  of  Zinc  Ore  at  FrankUn  Fiirnat'e,  Snssex  Co  ,  N.  ,1.,"  Anwr.  Join-.  Sci., 
Ma  J',   1882,  376.     Aug.  F.  Foer.ste,  "New  Fossil   Locahties  in   the  Early 
Paleozoics  of  Pennsylvania,  New  Jersey  and  Vermont,"  etc.,  Amer.  Jour. 
Sci.,  iii.,  XLVI.,  JUo.     Discusses  the  local  .stratigrai)hy  with  a  map.     P 
Groth,  "Die  Zinkerzlagerstatteu  von  New  Jevsi^y,"  ZcitKcliriJ't  fur  Pnih 
tische   Geologic,    May,  18!)4,    p.  '2'M).     W.  H.    Keating  and   L.  Vanuxeni, 
"Geology    and    Mineralogy    of    Franklin    in    Su.ssex    County,    N.   .].,' 
Jour.  Phila.  Acad.  i\at.  Sci.,  II.,  3TT,  1822.     Kec.    J.  F.  Kemp,  "The  Or." 
Deposits  at  Franklin  Furnace  and  Ogdensburgh,  N.  J.,"   Trann.   iV.  V. 
Acad.  Sci.,  XUL,  7()-98,  1893;  gives al'uli  hlltliograi)hy  and  annotated  Hst 
of  minerals.     Rec.     F.  L.  Nason,  Ann.  Rep.  Slalc  Gcol.,  X.  J.,  1890,  p.  2"); 
Amer.   Geol.,   VII.,    241;  VIII.,    Kiii;  XII.,    ir>4.     Amer.    Jour.    Sci.,    hi, 
XXXIX.,   407,   1890.     "The  Franklinite  Deposits   of  Mine   Hill,    Sus.scx 
County,  N.  J.,"  Tran.,.   A)ncr.  ln.st.  Min.  Encj.,  February,  1894;  Eng.  (iiid 
Min.  Jour..  Maj- 3,  1894,  p.  197.     Rec.     "Chemical  Comi)osition  of  .Soiiii' 
of  the  Wliite  Limestone  in  Sussex  Co.,  N.  i.,"  Amer.  Geol.,  March,  lSil4, 
p.  154.     T.  Nuttall.  "Geological  and  Minerah)gical  Remarks  on  the  Min- 
erals of  Paterson  and  on  the  Valley  of  Sparta,"  N.   Y.  Med.  ami  PIiijk. 
Jour.,  April,   May  and  June,   1822.     Amer.  Jour.  Sci.,  i.,   V.,  239,  1823, 
Jos.  C.  Piatt,  Jr.,  "The  Franklinite  and  Zinc  Litigation  Concerning  tlif 
Deposits  of  Mine  Hill  at  Franklin  Furnace,  SusscxCo.,  N.  J.,"  Trans.  Amer. 
Inst.  Min.  Eng.,  V.,  .WO,    1870-77.     II.  D.  Rogers,  "Geology  of  New  Jer- 
sey, 1849,  pp.  63-71,  with  a-  list  of  Minerals  by  Dr.  S.  Fowler."     Rec.     G.  C. 
Stone,  "Analyses  of    Franklinite  and  Some   Associated   Minerals    (two 
analyses  of  Zincite,   four  of  Franklinite,  Hve  of  Wihemite,  one  of  Tepli- 
roite),"  Scliool  of  Mines  Quarterli/,  VIII.,  148,  1887.     (i.  Troo.st.  "Ob.serva 
tions  on  tiie  Zinc  Ores  of  Franklin  and  Sterling,  Su.ssex  Co.,  N.  J.."  Jour. 
Phil.  Acad.   Nat.  Sci.,   IV.,  220,  1824.     .1.  P.   VVetiierell,  "The  Mine   Hill 
Ore  Depo.sits  in  New  Jer.sey  and  the  Wetherell  Concentrating P  ant,"  Eiuj. 
and  Min.  Jour.,  July  17.  1S97.     J.  D.  Wiiitney,   "Metallic:  Wealth  of  the 
United  States,"  p.  348,  18,-i4.     J.  E.  Wolff  and  A.  LI.  Brooks,  "The  Age  of 
the  Franklin  White  Limestone  of  Sussex  Co.,  N.  J.,"  XVIII.,  .1h J?.  Rep. 
Dir.  U.  S.    Geol.  Surrrif.  Part  II.,  pj).  ;2,-)-4.')7,    1899.     J.   E.   Wolff.  "Oc- 
currence of  Native  Coi»pcr  at  Franklin  Fuiuace.  N.  J.,"  J^roc.  Amer.  Acad. 
Arts  and  Sci.,  XXXIII.,  429,   1898.     "Hardy.stonite.  a  new  Calcium-zinc 
Silicate  from  Franklin  Furnace,  N.  J.,"  I'roc.  winter.  Ac((<l.   Arts  ((ud  Sci., 
XXXI v.,  479. 


Waemammmmma 


fObserva 


lit,"  ElKj. 


\{iin.  R<'P- 


ZINC  ALONE.  259 

lead-silver  or  copper-silver  ores  of  the  objectionable  zinc 
will  operate  favorably  on  many  mines  now  handicapped.  This 
has  already  proved  to  be  the  case  with  the  refractory  sulphides 
met  in  depth  at  Leadville. 

Deposits  of  oxidized  ores  in  southwestern  New  Mexico,  near 
the  town  of  Hanover,  have  recently  been  mined  to  a  notable 
extent.  The  smithsonite  and  calamine  as  well  as  the  blende, 
which  is  met  in  the  same  vicinity,  are  unmixed  with  galena,  but 
the  blende  often  contains  intermingled  pyrites.  The  ores  occupy 
irregular  caverns  and  seams  in  Paleozoic  or  Archean  limestone, 
iu  close  geological  association  with  intrusive  granite,  contact 
zones  and  iron  ores.  A  lenticular  shape  is  often  notable  in  the 
masses  of  blende.  As  remarked  by  Blake,  the  deposits  show 
some  interesting  points  of  resemblance  to  those  of  New  Jersey. 
The  richest  carbonates  and  calamine  have  been  shipped  to  the 
East,  but  with  the  unavoidably  high  freights  only  the  purest 
and  best  surface  ores  are  available.  (W.  P,  Blake,  "Zinc-ore 
Deposits  of  Southwestern  New  Mexico."  Trans.  Amer.  Inst. 
Min.  Eng. ,  XXIV. ,  187. )  Large  deposits  of  hv^matite  and  mag- 
netite have  been  worked  to  some  extent  in  the  same  region,  as 
a  flux  for  lead-silver  smelters,  but  their  remoteness  militates 
against  their  use  as  an  iron  ore. 

:?.()7.  n.  A  largo  amount  of  zinc  ore  is  turned  directly  into 
zinc  white  and  employed  as  a  pigment.  For  this  reason  the 
stiitistics  of  the  metal  do  not  indicate  all  the  ore  mined.  The 
accompanying  figures  are  short  tors.  For  detailed  statistics 
seethe  annual  volumes  on  "Mineral  Industry"  of  the  EiKjiix'er- 
iiKj  and  Miniiuj  Jovrnal,  ISDl:,  and  the  Annual  Reports  of 
the  U.  S.  Geological  Survey. 

1888.  1890.  1897. 

Illinois  and  Indiana ls,2()l  2(5.'M3  38,(i80 

Kansjis 7,300  15, 199  33,895 

Missouri 2,5(10  13,127  18,413 

Eastern  and  Southern  States 5, 098  9.114  9. 900 

33,705  03,083        100,387 

The  amounts  for  1882  and  1890  are  from  the  Mineral  Re- 
sources of  the  United  States,  1889-90.  p.  89,  those  for  1897 
are  from  the  Mineral  Industry,  VI.,  Ofil.  The  statistics  give 
the  metallurgical  output  for  the  several  States,  not  the  mining, 
hidiana  has  no  zinc  mines. 


:       t  i  ii. 


4^ 


i« 


tK  t 


CHAPTER    VIII. 


LEAD  AND   SILVER. 


2.08.01.  There  are  two  general  methods  of  extracting  silver 
from  its  ores,  the  one  indirectly,  by  smelting  with  and  for  lead; 
the  other  by  amalgamation,  chlorination,  or  some  such  procesH. 
Hence  under  silver  there  are  two  classes  of  mines — lead-silver 
and  high-grade  silver  ores.  Both  have  almost  always  vary- 
ing amounts  of  gold.  The  lead-silver  mines  furnish  also,  as 
noted  above,  by  fai*  the  greater  portion  of  the  lead  produced  in 
the  United  States.  Ores  adapted  to  lead-silver  metallurgical 
treatment  form,  in  general,  the  oxidized  alteration  products  of 
the  upper  parts  (above  permanent  water  level)  of  deposits  of 
galena  and  pja-ites.  They  may  be  well-marked  fissure  veins, 
chimneys,  chambers,  or  contact  deposits.  Ores  which  of  them- 
selves are  adapted  to  other  processes  are  often  worked  in  with 
the  lead  ores,  and  unchanged  sulphides  are  artificially  oxi- 
dized by  roasting  preparatory  to  smelting.  The  localities  are 
taken  up  geographically  from  east  to  west. 

2.08.0-*.  Lead-Silver  Deposits  in  the  Rocky  Moun- 
tain Region  and  the  Black  Hills.— The  mines  are  de- 
scribed in  order  from  south  to  north,  beginning  with  New 
Mexico. 

NEW    MEXICO. 

2.08.03.  Example  29.  The  Kelley  Lode.  Oxidized  lead 
ores,  with  some  blende,  calamine,  etc.,  forming  a  contact  de- 
posit betweim  slates  and  porphyry.  The  ore  body  is  in  the 
Magdalena  Mountains,  thirty  miles  west  of  Socorro,  and  has 
supplied  the  Billings  smelter  at  that  point.  Numerous  other 
ore  bodies  along  the  contact  between  sedimentary  and  eruptive 
rocks  occur  in  the  same  region. 

2.08.04.  Lake  Valley.    Farther  south  in  Doiia  Aiia  County 


PTWISl 


mam 


mtmmm 


LEAD  AND  SILVER. 


261 


the  mines  of  Lake  Valley  are  and  have  been  worked  upon 
deposits  very  closely  analogous  to  those  of  Leadville,  which 
furnish  the  principal  type.  They  contain  less  lead,  hardly 
enough,  in  fact,  to  he  classed  as  lead -silver  ores,  according  to 
the  recent  valuable  paper  of  Ellis  Clark,  although  earlier 
descriptions  place  greater  emphasis  on  the  presence  of  carbon- 
ates of  this  metal.  According  to  Clark,  the  geological  section 
involved  includes  quartzite  and  limestone,  considered  Silurian, 
(;(iO  feet;  Lower  Carboniferous,  black  shale,  100  feet;  green 
shale.  flO  feet;  nodular  limestone,  4iS  feet;  blue  limestone,  24 
feet;  crinoidal  limestone,  I'-io  feet,  and  overlying  limestone,  oO 
feet;  about  1,000  feet  in  all.  These  are  penetrated  by  four 
distinct  eruptions  of  igneous  rocks,  hornblende-andesite,  rhyo- 
lite,  obsidian  and  porphyrite.     The  obsidian  is  comparatively 


Fig.  93. — Geological  cross  section  of   Lake    Valh y,   2\tio  Mixiro,  to  nh<-in  the 

rcldtions    of  the    ore.     The    black  mass  is  ore;  the    dark  hachiires 

in  the  lower  left-hand  corner  are  black  shale.     After  Ellis 

Clark,  Trans.  Amer.  Inst.  Min.  Kng.,  XXIV.,  p.  155. 

unimportant,  and  of  the  others  tho  porphyrite  is  most  inti- 
mately associated  with  the  ore.  The  ore  bodies  are  always 
connected  with  the  blue  limestone,  and  lie  along  the  contact  of 
tins,  either  with  the  porphyrite  or  the  overlying  crinoidal 
limestone.  They  are  in  the  nature  of  large  chutes  or  elongated 
contact  deposits,  very  similar,  as  the  figure  will  indicate,  to 
those  at  Leadville. 

Tiie  ores  are  of  several  varieties  but  the  general  components, 
in  addition  to  the  silver,  are  silica,  oxides  of  iron  and  manga- 
nese, limestone,  some  galena  at  times,  and  some  zinc. 

The  varying  percentages  of  the  silica  and  bases  atVord  basic, 
neutral  and  siliceous  ores.  In  the  bonanza  called  the  Bridal 
Chamber,  great    masses    of  horn-silver    were    found.     Many 


262 


KEMP'S  ORE  DEPOSITS. 


ores,  and  interesting  metalH,  such  as  vanadinite,  descloizite,  etc., 
have  made  tlie  district  well  known  to  collectors.  Clark  favors 
the  view  that  the  leaching  of  the  porphyrite  (which  is  argentifer- 
ous) during  its  exposure  and  erosion,  by  descending  surface 
waters,  has  been  the  source  of  the  ore.  An  earlier  view  attrib- 
uted it  to  uprising  currents. ' 

COLORADO. 

2.08.05.  Example  ;]0.  Leadville.  Bodies  of  oxidized  lead- 
silver  ores,  passing  in  depth  into  sulphides,  deposited  in  much 
faulted  Carboniferous  limestone,  in  connection  with  dikes  and 
sheets  of  porphyry.  Leadville  is  situated  in  a  valley  wliich  is 
formed  by  the  head  waters  of  the  Arkansas  River.  The  valley 
runs  north  and  south,  being  confined  below  by  the  closing  iu 
of  the  hills  at  the  town  of  Granite.  It  is  about  twenty  miles  long 
and  sixteen  broad,  and  even  to  superficial  observation  is  seen  to 
be  the  dried  bottom  of  a  former  lake.  The  mountains  on  the  eawt 
form  the  Mosquito  range,  a  part  of  the  great  Park  range,  while 
those  on  the  west  are  the  Sa watch,  and  constitute  the  Continen- 
tal Divide  at  this  point.  Leadville  itself  is  on  the  easterly 
side,  upon  some  foothills  of  the  Mosquito  range.  The  eastern 
slope  of  the  Mosquito  range  rises  quite  gradually  from  the 
South  Park  to  a  general  height  of  lli.OOd  feet.  The  range  then 
forms  a  very  abrupt  crest,  with  steep  slopns  looking  westward, 
which  are  due  to  a  series  of  north  and  south  faults  whose  east- 
erly sides  have  been  heaved  u[)ward  as  much  as  7,500  feet.  The 
faults  pass  into  anticlines  along  their  strike.  The  Mosquito 
range  consists  of  crystalline  Archean  rocks,  foliated  granites, 
gneisses,  and  amphil)olites,  and  of  over  5,000  feet  of  Paleozoic 
sediments  and  igneous  rocks.  The  former  include  Cambrian 
quartzite,  150  to  ^iOOfeet;  Silurian  white  limestone,  KiO  feet, 
and  quartzite,  40  feet;  Carboniferous  blue  limestone,  200  feet 
(the  chief  ore-bearing  stratum) ;  Weber  shales  and  sandstones. 
2,000  feet;  and  Upper  Carboniferous  limestones,  1,000  to  1,5(HI 
feet.  The  igneous  rocks  are  generally  porphyries.  The  sedi- 
mentary rocks  were  laid  down  in  Paleozoic  time  on  the  shores 

'  E.  Clark,  "Tlie  Silver  Mines  of  Lake  Valley,  N.  M.,"  Trans.  Aiiier. 
Inst.  Mill.  Eng.,  XXIV.,  188,  185)4.  Rej).  of  Director  of  the  Mint,  1882,  Lake 
Valley.  )>.  841;  Kelley  Lode,  p.  37(5.  B.  Silliinan,  "Mineral  Regions  of 
New  Mexico,"  Trcms.  Amcr.  Inst.  Min.  E)i(j.,  X.,  224. 


ssasis 


MMtMMM 


■HMiiii 


LEAD  AND  SUA' Kit. 


2G:1 


gions 


of  the  Archean  Sawatch  Island,  ami  were  penetrated  by  tlio 
igueoiis  rocks,  probably  at  the  close  of  the  Cretaceous.  They 
wore  all  upheaved,  folded,  and  faulted  in  the  general  elevation 
of  the  Rocky  Mountains,  about  the  beginning  of  the  Tertiary 
period.  The  intrusion  of  the  igneous  rocks  was  the  priine 
mover  in  starting  ore  deposition,  and  the  solutions  favored  the 
under  sides  of  the  sheets,  along  their  contacts  with  the  blue 
Carboniferous  limestone. 

2.08.0().  The  early  history  of  Leadville  will  be  subsequently 
referred  to  in  speaking  of  auriferous  gravels.  The  lead-silver 
or«s  first  became  prominent  in  1877,  although  discovered  in 
1ST4.  and  by  isso  the  develo})ment  was  enormous.  The  region 
grow  at  once  to  be  the  ku'gest  single  producer  of  these  ores,  and 
lias  remained  such  ever  since.  The  mines  are  situated  east  of 
the  city  on  the  three  low  hills,  Fryer^  Carbonate  and  Iron,  but 
recently  a  deep  shaft  in  the  city  itself  has  found  the  extension 
of  the  ore  chutes  and  opened  up  great  future  supplies.  The 
ores  have  chiefly  come  in  the  past  from  the  upper  oxidized  por- 
tions of  the  deposits.     Of  late  years,  however,  the  older  and 

eper  workings  have  been  showing  the  unchanged  sulphurots. 


(I* 


The  ores  are  chiefly  earthy  carbonate  of  lead,  with  chloride  of 
silver,  in  ;i  clayey  or  siliceous  mass  of  hydrated  oxides  of  iron 
and  manganese.  In  the  Robert  E.  Lee  mine  silver  chloride 
occurred  without  lead.  Some  zinc  is  also  found,  and  a  long 
list  of  rare  minerals.  Where  the  ore  is  in  a  hard,  siliceous, 
limonite  gangue  it  is  called  hard  carbonate,  but  where  it  is 
saudy  and  incoherent  it  forms  a  soft  carbonate,  or  sand  carbon- 
ate. All  the  older  mines  produce  small  amounts  of  gold,  but 
iu  some  newer  developments  the  gold  is  of  more  importance 
than  the  silver.  A  few  ore  bodies  are  found  at  other  horizons 
than  the  Carboniferous.  They  also  run  in  instances  as  much 
as  lOU  feet  from  the  contact,  and  may  likewise  be  found  in  the 
porpliyry,  doubtless  replacing  included  limestone.  Thej'  were 
all  deposited  as  sulphides,  and,  according  to  Emmons,  when 
the  rocks  were  at  least  10,000  feet  below  the  surface. 

In  IS'.n  and  ISD'^  great  interest  centered  in  the  liscovery  and 
development  of  ore  bodies,  whose  values  in  gold  much  ex- 
ceeded those  in  silver,  and  which  were  situated  further  east 
from  the  city  of  Leadville  than  the  older  silver  mines.  The 
gold  output  has  now  proved  very  considerable,  although   lim- 


m 

ii 

LEAD  AND  SILVER. 


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ited  to  but  few  mineH.  The  geological  asHooiations  are  much 
the  same  as  in  the  older  workiugH,  and  indeed  the  gold  ores 
occur  on  the  extended  lines  of  the  older  chutes,  when  ju-ojectod 
to  the  eastward. 

•i.(is.()7.  In  the  valuable  monograph  on  the  region,  which  is 
now  a  chissic  on  the  subject,  and  which  is  cited  below,  Em- 
iiums  endeavors  to  prove  the  following  jioints: 

I.  That  the  ores  were  deposited  from  aijueous  solution. 

II.  That  they  were  originally  deposited  mainly  in  the  form 
of  Hiiljihidea. 

III.  That  the  process  of  deposition  involved  a  metasomatic 
interchange  with  the  njaterial  of  the  rock  in  which  they  were 
deposited, 

IV.  That  tlie  mineral  solutions  or  ore  currents  were  concen- 
trated along  natural  water  channels,  and  followed,  by  prefer- 
ence, the  bedding  planesat  a  certain  geological  horizon,  but  that 
they  alst)  penetrated  the  adjoining  rocks  through  cross  joints  anil 
cleavage  cracks. 

Th(?Ho  additional  points  are  also  advanced: 

I.  That  the  solutions  came  from  above. 

II.  That  they  were  derived  mainly  from  the  neighboring 
eruptive  rocks. 

-'.OS. OH.  The  first  four  points  are  doubtless  correct,  and  No. 
III.  is  an  important  application  of  the  theory  of  replacement, 
fre(juently  referred  to  in  the  introduction.  The  last  two  propo- 
sitions merit  less  confidence.  Seven  additional  years  of  mining 
have  brought  many  new  facts  to  light,  and  have  led  others 
(A.  A.  Blow  in  particular,  whoso  valuable  paper  is  cited 
below)  to  refer  the  ores  to  upward  rising  currents.  Emmons 
foresaw  this  possibility  and  mentioned  it  on  p.  5.S4  of  his  mono- 
graph. The  amount  of  the  adjacent,  igneous  rocks  is  quite 
insutlicient  to  afford  the  ore.  In  alteration  the  galena  has 
passed  through  an  intermediate  stage  of  sulphate  before  chang- 
ing to  carbonate.  These  mines  have  been  important  not  alone 
in  their  own  metallic  products,  but  in  furnishing  the  smelters 
with  oxidized  lead  ores,  they  have  supplied  a  means  of  reduc- 
tion for  many  other  more  refractory  ones,  which  could  be  con- 
veniently beneficiated  through  the  medium  of  lead.^  Much 
copper  occurs  with  the  sulphides  now  met  in  depth. 

'  F.  M.  Amelung,  "The  Geology  of  the  Leadville  Ore  District,"  Eng. 


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KHMrS  ORh'  DEI'OSn'S. 


^.OH.ot).  ExHinplo  '6{)(i.  Ten  Mile,  Summit  County.  Hod- 
ies  of  argontiforouH  galena,  pyrite,  blende  and  their  oxidi/tMl 
productH  replacing  or  impn^gnating  bedH  of  Upper  Carbonifer- 
OUH  limeHtone,  or  filling  HHHuro  veins.  The  geological  section 
at  T(>n  Mile  resembles  that  of  Ltiadville,  which  lies  IS-'^O  miles 
south,  but  the  productive  strata  are  in  the  Upper  Carbonifer- 
ous or  Maroon  formation,  instead  of  in  the  Lower  Carboniferotis 
or  Lcadville  limestone.  The  Maroon  formation  is  chiefly 
sandstoi.es.  It  is  estimated  at  1,500  feet  thick,  and  is  separated 
from  the  Leadville  blue  lim{>8tone  by  ;500  feet  of  Weber  grits. 
It  contains  several  thin  beds  of  limestones  in  connection  with 
which  some  of  tho  ores  are  found.  'I'he  ore  bodies  present  at 
least  two  types.  The  first  is  illustrated  by  the  Robinson  mine, 
P'ig.  Itf,  in  which  the  ore  lies  along  two  small  faults  and 
replaces  the  limestone  between  and  on  either  side  of  them.  In 
this  as  in  the  other  mines  tho  chief  mineral  in  theunoxidized  })or- 
tion  is  pyrite,  or  marcasite  or  pyrrhotito.  With  one  or  the  other 
of  these  aro  smaller  amounts  of  galena  and  blende.  The  oxi- 
dized portions  proved  the  richest,  the  others  recjuire  concen- 
tration. The  fissure  vein  type  is  illustrated  by  the  Queen  of  the 
West  mine,  whose  ores  were  found  in   several  parallel  fault 


and  Mill.  Jour.,  April  16,  ISSO,  p.  25.  "Ou  tlie  Origin  of  tlie  Ove,"  Ibid  . 
Dec  en  I  her  '..'(I,  1879.  A.  A.  Blow,  "  The  (Jeoioj^'y  and  Ore  Deposits  of  Imu 
Hill,  Leadville,  Colo.,"  Tnai.s.  Amcr.  Inst.  Min.  Kutj.,  XVIII.,  145,  \my 
Ke(^  Ann.  Rep.  Colo.  School  of  Mines,  ISHT,  p.  (}3.  "The  Leudvilie 
(iold  Belt,"  Eng.  and  Min.  Jour.,  .January  2(i,  lM!tr>.  Kec.  Maps.  S.  F. 
Eninioiis,  "Geology  and  Mining  Industry  of  Leadville,"  Monocir(ii)h  I.'. 
U.  S.  Geol.  ISnrcey.  Rec.  Second  ^\nn.  Hep.  Dinrlor  of  IL  S.  ilrol.  Snr 
vey.  Ree.  jfV«^/i  Cctjsms,  Vol.  Xlll.,  j).  7(1.  F.  T.  Freeland,  "The  Sul 
]>Iiide  Deposits  of  South  Iron  Hill,  Leudvilie,"  Trims.  Anier.  Inst.  Min. 
Eng.,  XIV.,  181.  C.  Henrieh,  "The  Character  of  the  Leadville  Ore 
Deposits,"  Eng.  and  Min.  Jour.,  Deeeniher  27.  187!*,  p.  470.  "Origin  nl 
the  Leadville  Deposits,"  Eng.  and  Min.  Jonr.,  May  12.  I8SS,  p.  4:5.  "On  tlir 
KveningStur  Mine,"  Ihid.,  Jlay  7,  IHSl,  p.  ;{(ii.  "i,eadville  (ieology,"  Ibiil., 
June  3  and  10,  18H2;  "Ilistoricial,"  May  30,  Aiu-il  0,  13,  20,  27,  1H7H;  also 
many  other  allusions,  1879-81.  R.  W.  Raymond,  "Report  on  the  Little 
Pittshurg  Mine,"  Eng.  <nid  Min.  Johc,  .Line  28,  1879.  L.  D.  Riekett.s. 
"The  Ores  of  Leadville,"  Princeton,  1883.  C.  M.  Rolker,  "Notes  on 
Leadville  Ore  Depasits,"  Trans.  Ainer.  Inst.  Min.  Eng.,  XIV.,  273,  i'4!). 
F.  L.  Vinton,  "Leadville  and  the  Iron  Mine,"  Eng.  and  Min.  Jour..  IVb 
ruary  15,  1879,  p.  110;  also  Juno  28,  p.  45.  A  series  of  short  p:ii't'i"'^ 
on  "The  Gold  Belt"  was  puhlished  in  1894,  by  the  Leadville  Chambi'r  oi' 
Commerce. 


LEAD  AND  STLVKR. 


20  r 


ts  of  lion 

in,  ISS'.I 
Letulville 
S.  F. 
vitpli  '■' 
h'ol.  Siir 
Tlui  Snl 
s/.  .1/''" 
vill«  Oiv 
)rigin  "I 
•'Ontlif 
y,"  Ibiil: 
ISTS;  alsn 
tlie  Little 
Ricki'lts. 
Notes  oil 
,  273,  iUi). 

rt   r:i|"''" 
hamb.'i-  "!' 


fiHHures,  as  showu  iu  Fig.  Itr).  The  ores  were  rich  in  the  oxi- 
dized zone,  but  grew  lean  in  tlie  sulphides.  In  the  White 
(,^)iiail  typo  the  ores  aro  somewhat  less  <leMuitely  circumscribed. 
Tiiey  still  form  elongated  replacomentw,  but  contain  consider- 

'.'v.vv.-.j,  ..•      ■:.        "     ■     "     .'■:,.. 


t 


Biindstono 
i  Slittlu 
LImuatoue 


Fl(».  04. — Section  throiKjh  thi' No.  "i  orf.t'finh'  nftlic  lloltiiiHon.  iniiii\   Ti  n-mile 
district,  C'ulo.     After  <S.   /''.    h'tiniiniiK,    Tin-ndli'.  Special  Folio, 
U.  8.   Gvohxjicdl  Siiri'(i/. 


No.3.Sh 


Firt.  05. — Cross-section,  Queen  oj  the  Went  nnnr.  Ten  mile  district,  Colo.     Ihe 
rich  ore  appeiirn  in  the  darker  vertical  hands.     After  S.  fi\  Amnions, 
Ten-mile  Special  Folio,    U.  S.  Geological  Survey. 

able  <niartz,  calcite  and  harite.  They  shade  out  laterally  into 
jasperoid  quartz,  which  is  succeeded  by  barren  limestone.  The 
amount  of  sulphides  is  enormous.' 

'  S.  F.  Emmons,  lYnth  Cen.'iiot.  Vol.  XIII.,  p.  73.  Ten  Mile  Sjjecial 
Folio,  1H9!).  Rec.  The  above  description  has  been  cliieHy  drawn  from 
thi.s  folio. 


268 


KEMP'S  OliK  DEPOSITS. 


I 


'ft 


2.08.10.  Example  306.  Monarch  district,  Chaffee  Coimty. 
Oxidized  lead-silver  ores  in  limestone.  The  helt  of  limestones 
south  from  Leadville  contains  some  notable  ore  bodies  in  Chaf- 
fee County.  The  Monarch  district  is  the  most  important.  It 
is  situated  at  the  head  wat'^rs  of  a  branch  of  tbe  South  Arkan- 
s.is  River.  The  ore  lies  in  limestones  whose  age  is  not  yet  accu- 
rately determined.  The  Madonna  mine  is  the  best  known  and 
has  shipped  much  ore  to  Pueblo.' 

3.08.11.  Example  o(»c.  Eagle  River,  Eagle  County.  Galena 
and  its  alteration  product,  anglesito,  in  Carboniferous  lime- 
stone, on  the  contact  between  it  and  cpiartzite  or  porphyry. 
The  mines  lie  in  the  valley  of  Eagle  River,  on  the  western 
slope  of  the  Continental  Divide.  Tlie  galena  has  changed  to 
the  sulpbate,  instead  of  carbonate,  prcjbably  having  been  less 
completel}'  oxidized  than  at  Leadville,  and  marking  the  inter- 
mediate stage  in  the  process.  The  wall  rocks  lie  (^uite  undis- 
turbed, having  a  low  dip  of  1.')°  north,  and  nut  being  faulteil. 
Lj'ing  lower  than  tbe  lead-silver  deposits,  and  in  Cambrian 
(juartzite,  on  tbe  contact  v/ith  an  overlying  sandstone,  are  found 

chutes  carrying  gold  in  talcose  clay." 

2.08.13,  Example  odd  Aspen,  Pitkin  Count)'.  Bodies  of 
lead -silver  ores,  largely  oxidized,  occurring  with  much  barite, 
cbietly  at  the  intersections  of  a  series  cf  vertical  cross-faults, 
with  ^wo  bed  faults  in  Carboniferous  limestone  and  dolomite; 
but  also  :n  less  important  amounts,  although  in  similar  rela- 
tions to  faults,  in  strata  both  older  and  later.  Aspen  is  on  the 
western  slope  of  tbe  Continental  Divide,  in  the  valle}'  of  tlui 
Roaring  Fork,  just  at  the  point,  where  it  crosses  the  contact  of 
crystalline  Archean  gneisses  and  Paleozoic  sediments.  The 
stream  cuts  them  at  right  angles  to  the  strike.  Aspen  Moun- 
tain  lies  on  the  south   side,  and   Smuf  sjler  Mountain   on  the 


'  S.  F.  Emmons,    Tenth  Census.   Vol.    XIII.,  p.   79.     Rep.    Director  of 
the  Mint,  1884,  p.  181. 

'  S.  F.  Emmons,  "  Notes  on  some  Colorado  Ore  Deposits,"  Colo.  Sci. 
Soc,  Vol.  IT..  Part  II.,  p.  100.  E.  E,  Olcott,  "  Battle  .Mountain  Mining' 
Distri(^t,  Eagle  County,  Colorado,"  Emj.  (tint  Min.  Jour..  June  11,  18sT.  jip 
417,  43(i:  ")i<l..  May  21,  1892,  p.  Ur>.  G.  C.  Tilden,  "  Mining  Notes  fnmi 
Eagle  County,"  Ann.  Rep.  Colo.  State  Sehool  of  ,V/;(c.s',  1880,  j).  29. 


LEAD  AND  SILVER. 


269 


luuty. 
stones 
Chaf- 
it.  It 
^rkan- 
;  accu- 
yrn  and 

3aleua 
1   lime- 
•pbyry. 
.vesteru 
Liged  to 
36  u  less 
9  inter- 
3  uiidis- 
faulteil 
mibrian 
re  found 

Jodies  of 
h  bavite, 
s-faults, 
olomiti' ; 
liar  rela- 
is  on  the 
y  of  thu 
lontact  of 
ts.     The 
1    Monii- 
1   on  the 


)i recto 

•    0/ 

Colo. 

Svi. 

in    Mining-' 

1.18S-: 

.  IT- 

Ndtes 

from 

2y. 

""— —^n 


li 


270 


KEMP'S  ORE  DEPOSITS. 


north.     The  limestone  belt  continues  north  and  south,  and  is 
prospected  over  a  stretch  of  nearly  forty  miles. 

2.08.  lo.  The  geological  section  at  Aspen  embraces  the 
following  strata,  which  have  been  carefully  determined  and 
measured  by  J,  E.  Spurr.  Upon  the  Archean  granite  rests  the 
Sawatch  formation  of  the  Cambrian,  200  to  400  feet  thick. 
Begmning  as  a  thin  conglomerate,  it  passes  into  a  quartzite 
and  then  into  a  sandy  dolomite.  The  Yule  formation  of  the 
Silurian  is  a  dolomite,  250  to  400  feet  in  thickness.    The  Parting 


Fig.  97a. — Cross  section  of  the  Dpila  Fl.  Mine.  Slmnjrjlpr  Movvfnin.  Aspen. 

Colo.     After  J.  E.  Spin-r.   Moiiogrfij)}!   XXXI.    l^.  S.   Geological 

Survey,  Plate  XLII.,  b.  Section  through  the  Durant  and 

Aspen  Mines,  hii  D.  Rohljing.  Mem,  Plate  XL.- 

■  The  black  is  ore. 


Quartzite,  Devonian,  GOfoet  thick,  lies  above.  The  Carbonifet- 
ouH  has  three  members.  The  lowest  is  the  Leadville  limestone, 
of  which  200  to  -Irti)  feet  is  a  brown  dolomite,  and  100  to  150  feet 
H  blue  limestone,  the  two  being  separated  by  the  "Contact"  bed- 
fault.  Above  the  LeadvMle  limestone  are  the  Weber  shales  aud 
carbonaceous  limestone,  1,000  feet  or  more;  and  the  Maroon 
grits,  4,000  feet.  The  Mesozoic  beds  which  rest  on  the  last 
named  are  very  thick,  but  have  no  important  relation  to  the 
ore. 


LEAD  AND  SILVER. 


271 


3.08.14.  Aside  from  the  Archean  granite  there  are  two 
eruptive  rocks  in  the  district.  A  diorite- porphyry  forms  a  sheet 
at  and  below  the  Parting  Quartzite,  and  thickest  at  the  south, 
but  thinning  to  the  north.  A  cjuartz-porphyry,  very  like  the 
"White  Porphyry"  at  Leadville  (compare  Fig.  X\),  is  400  feet 
thick  on  Aspen  Mountain,  but  it  thins  out  both  to  the  north 
and  the  south.  It  appears  near  the  base  of  the  Weber  shales. 
The  age  of  both  the  porphyries  is  probably  late  Cretaceous. 

2.08.15.  After  the  deposition  of  the  Laramie  beds,  of  the 
Cretaceous,  a  compressive  force  from  the  west  developed  an 
overturned  anticline,  which  culminated  in  a  great  fault  along 
Castle  Creek,  to  the  west  of  the  mines.  A  syncline  Avas  pro- 
duced on  the  east  limb  of  the  great  anticline,  and  was  later 
domed  upward  by  an  uplift,  which  gave  the  trough  a  marked 
pitch  to  the  north.  During  the  folding  two  faults  were  jiroduced 
parallel  with  the  bedding  of  the  Leadville  limestone.  One  runs 
along  at  the  contact  of  the  dolomite  and  the  blue  limestone 
(the  "Contact"  fault);  the  other  follows  the  contact  of  thf  blue 
limestone  and  the  Weber  shales  (the  "Silver"  fault).  Many 
cross-faults  were  also  formed  at  about  this  time,  which  inter- 
sected the  bed-faults,  but  along  which  movement  seems  to  be 
8till  in  progress.  At  a  certain  stage  ore-bearing  solutions 
appear  to  have  circulated  along  the  bed-faults,  and  are  thought 
by  J.  E.  Spurr,  to  have  been  precipitated  by  other  solutions  in 
the  cross-faults,  so  that  the  shattered  rock  at  the  intersections 
became  replaced  with  ore.' 

3.08.1(1.     Example    'M)e.     Rico,   Dolores    County.     Contact 
deposits  of  lead-silver  ores,  in  Carboniferous  limestones,  along 


'  D.  \V.  Bninton.  "Aspen  Mountcain :  Its  Ores  and  Mode  of  Occiirreuce," 
Ewj.  inid  Min.  Juki:,  July  14  atid  'Jl,  l^fSH,  pp.  -i-,',  42.  S.  F.  EiniiKms, 
"P'cHininary  Notes  on  Asi)en,"  I'rac.  Colo.  Sci.  Soc,  Vol.  II.,  Part  III., 
p.  ~r)l  Ree.  C.  Henrieh,  "Notes  on  tlie  Geology  and  on  some  of  tlie 
5Iines  of  .\spen  Mountain,"  'Jraiis.  Amrr.  Inst.  Mhi.  Eiiij.,  XVII.,  I.IG.  A. 
L'lkes,  "(ieology  of  tlie  Aspen  Jlining  Region,"  Ann  Rep.  Colo.  ScJiool  of 
Mini's,  ISSC).  W.  E.  Newbeny,  "Notes  on  the  Geology  of  the  Aspen 
Mitiing  District,"  Tmiis.  Amer.  Innt.  Min.  Emj.,  XVII.,  27:^  1889.  Rec. 
L.  1».  Silver,  "Geology  of  the  Aspen  (Colo.)  Ore  Deposits,"  Eng.  and  Min. 
<\iHr.,  March  17  and  24,  1888.  J.  E.  Sjmrr,  "Geology  of  Asjieu  Mining 
District,"  U.  S.  Geol.  Survey,  Monogra|)h  XXXI.,  18i)9.     Reo. 


t 


272 


KEMP'S  ORE  DEPOSITS. 


sff^ 


intrusive  porphyries.  Considerable  base  bullion  has  been 
shipped.  There  are  coals  in  the  vicinity,  but  the  operation  of 
the  smelter  has  been  somewhat  intermittent.  The  Newman 
Hill  mines  are  mentioned  under  "Silver."  ' 

Note, — Example  .'JO/  will  be  found  after  Example  31,  which 
has  been  inserted  for  geographical  reasons. 

2.08.17.  Example  ol.  Red  Mountain,  Ouray  County. 
Oxidized  lead-silver  ores  passing  in  depth  into  sulphides,  in 
large  and  small  cavities,  in  knobs  of  ailicified  andesite.  The 
cavities  have  a  close  resemblance  to  caves,  but  differ  from  ordi- 
nary caves  in  not  being  in  limestone.  They  permeate  the 
mountain  in  an  irregular  Avay,  and  mark  the  courses  of  old  hot 
spring  conduits.  The  ande<^ite  is  generally  altered  to  a  mass 
of  quartz,  but  the  process  is  thought  b}'  S,  F,  Emmons  to  have 
taken  place  at  a  considerable  de})th,  and  that  the  (quartz  is  a 
residual  deposit  left  by  the  removal  of  more  soluble  elements 
of  the  andesite.  T.  B.  Comstock  regards  them  as  hot  spring 
deposits.*^ 

SOUTH    DAKOTA. 

2.08.18.  Example  30/,  Galena  (town),  in  the  Black  Hills. 
Deposits  of  galena  in  part  altered  to  carbonate,  in  Cambrian 
(Potsdam)  sandstone,  near  intruded  sheets  of  trachyte.  The 
ore  occurs  in  local  enrichments  distributed  at  irregular  inter- 
vals through  the  sandstone.  It  is  rarely  found  in  the  overly- 
ing limestones  of  the  Carboniferous.  The  ore  bodies  are  closely 
akin  to  the  so-called  "siliceous,"or  "Potsdam"  gold  ores,  later 
described.    Galena  and  Carbonate  are  the  best  known  localities.' 


'  M.  C.  Ililseng,  "Review  of  the  Mining  Regions  of  the  SanJuau, " 
Ann.  Rep.  Colo.  School  of  Mines,"  1885,  p.  43. 

'  T.  B.  Comstock,  "  Hot  Spring  Deposits  in  Red  Mountain,  Colorailo," 
Trans.  Anier.  Inst.  Min.  Eikj.,  XVIII.,  2(U.  S.  F.  Eninioiis.  "Notes  on 
Some  Colorado  Ore  Deposits,'  Proc.  Colo.  Sei.  Sac  Vol.  II.,  Part  II..  j). 
97.  M.  C.  Ihlseng,  "Review  of  the  Mining  Interests  of  the  San  Jiiaii 
Region,"  Ann.  Re}).  Colo.  School  of  Mines,  1885,  j).  4(5.  T.  E.  SL-hwartz, 
" The  Ore  Deposits  of  Red  Mountain,  Colorado,"  Trans.  Atner.  In-sLMin. 
Encj.,  XVIII.,  i;3i>,  188!);  Proc.   Colo.  Sci.  Soc,  Vol.  III.,  Part  I.,  p.  77. 

'  F.  R.  Carpenter,  "Ore  Deposits  of  the  Bhu-!.  Hills  of  Dakota,"  Triinn. 
Amer.  Inst.  Min.  Emj.,  1889,  Vol.  XVII.,  p.  570.  See  al.so  report  hy  Or. 
Carpenter  on  the  geology,  etc.,  of  the  Black  Hills,  to  the  trustees  of  the 
Dakota  School  of  Mines,  1888.  p.  124.  S.  F.  Emmons,  Tenth  Census,  Vol. 
XIII.,  p.  91. 


LEAD  AND  ISILVEB. 


373 


i  been 
tion  of 
3\vman 

,  which 

>unty. 
ides,  in 
9.     The 
)ni  ordi- 
3ate  the 
'  old  hot 
)  a  mass 
to  Imve 
rtvtz  is  a 
Blenients 
»t  spring 


pk  Hills. 
Jambrian 
te.     The 

ir  inter- 
overly - 
:e  closely 

es,  later 
jcalities.' 

SanJuau, " 

dloratl'^." 
Notes  en 
ait  n..  I'- 
8au  Juiiii 
Schwartz. 
liiHt.Mii> 

.,  p.  '<"'' 
ta,"  Traiiii. 
)()vtV)y  U«-' 
U>es  of  the 
'(■/).s((.s,  Vol. 


MONTANA — IDAHO, 

2.08.19.  Example  '.i2.  Glendale,  Beaver  Head  County. 
Ore  bodies  of  argentiferous  galena,  ziucblende,  copper  and  iron 
pvrites,  and  their  oxidation  products,  occurring  parallel  with 
the  sti'atitication  planes  of  a  blue-gray  limestone,  of  age  not  yet 
determined.  These  deposits  constitute  the  Hecla  mines,  and 
are  in  the  sotithwestern  part  of  the  State.  They  ofiPer  some 
parallel  features  with  those  of  southeastern  Missouri.  (Exam- 
ple •.';>.)  They  differ  from  Example  '^O  in  net  being  associated, 
so  far  aa  known,  with  igneous  rocks.' 

2. OS. -30.  Example  ;}'^«.  Wood  River,  Idaho.  Bodies  of 
iiigeiitit'erous  galena  and  alteration  products,  irregularly  dis- 
tributed in  limestone,  of  age  as  yet  undetermined.  Southwest- 
ern Idaho  is  largely  formed  of  granite,  southeastern  is  cov- 
ered by  the  innnense  fissure  outpourings  of  basalt  along  the 
Snake  River.  North  of  these,  and  on  the  flanks  of  the  gran- 
ite, are  slates  and  limestones,  especially  on  the  Wood  River.  The 
latter  contain  the  lead-silver  ores.  They  are  not  in  immediate 
association  with  igneous  rocks,  and  from  published  descriptions 
ajipear  to  be  somewhat  irregularly  distributed,  although  possi- 
bly connected  with  fissures.  The  stuctural  relations  with  Ex- 
ample 2.)  may  again  l)e  referred  to.  The  neighboring  slates 
and  granite  contain  gold  and  silver  veins,  which  are  taken  up 
later  on.  Several  small  smelters  have  been  erected  in  the 
region,  and  have  been  intermittently  operated.  The  country 
is  really  in  the  northern  end  of  the  Great  Basin. '^ 

■^.08.31.  Example  '.]^i.  Wickes,  Jefferson  Count}',  Mont. 
Fissure  veins  near  the  contact  of  granite  and  liparite,  but  cut- 
ting both  rocks  and  carrying  in  a  gangue  of  quartz  the  ores, 
galena,  ziucblende,  cop])er  and  iron  pyrites,  and  mispickel. 
The  liparite  is  said  bj'  Lindgren  to  be  Cretaceous  or  Tertiary. 
Wickes  is  just  south  of  Helena,  and  was  one  of  the  first  places 
ill  the  West  to  establish  successful  concentration.  There  are 
two  companies,  the  Helena  and  the  Gregory,  both  large  pro- 
•liKX^rs. 


'  S.  F.  Emmons,  Tenth  Cemus,  Vol.  XIII.,  p.  97. 

■  G.  F.  Becker,  Tenth  Census,  Vol.  XIII.,  p.  55.  Eng.  and  Min.  Jour., 
•Inly  2,  18ST,  p.  2.  Rep.  Di.eetor  of  the  Mint,  1882,  p.  198.  G.  H.  P^klredge, 
XVI.;  Ann.  Rep.  Dir.  U.  S  Geol.  Surrey,  II.,  264.  Rec.  J.  B.  Hastings, 
Eng.  and  Min.  Jour.,  March  25,  1895.  208. 


274 


KM  MPS  ORE  j>h'rosrrs. 


3.08. 2l>.  Example  ;34.  Ca'ur  d'Alene,  Idaho.  Galena  and 
very  subordinate  alteration  productH,  in  a  mineralized  zone 
having  a  well-marked  footwall  and  tin  impregnated,  brecciated 
hanging  of  the  same  rock.  The  ore  is  in  large  cliutes,  which 
fill  innumerable  small  fractures  in  the  rock.  The  mines  are  in 
Wardner  (*anoti,  in  the  Bitter  Root  Mountains,  northern 
Idaho.  The  I'ocks  are  quartzite,  and  thin  beds  of  schists,  much 
folded  along  east  and  west  axes.  In  this  way  they  became 
faulted  and  shattered,  and  in  the  ])rincipal  mineral  belt  afforded 
aia  opportmiity  for  the  ore  to  deposit.  The  gangne  is  siderite. 
The  mines  are  extremely  productive  and  are  the  chief  sources 
of  ore  supply  for  lead  smelters  in  jMontana  and  on  the  Pacific 
coast.'     Detailed  descriptions  are  much  needed. 

UTAH. 

2.08.23.  Example  35.  Bingham  and  Big  and  Little  Cot- 
tonwood Canons,  Utah.  Bed  veins,  often  of  great  size,  contain- 
ing oxidized  lead-silver  ores  above  and  galena  and  pyrite  below 
the  water  level,  in  Carboniferous  limestones,  or  underlyiuii; 
quartzite,  or  on  the  contact  between  the  two.  The  mines  are 
situated  in  the  Utjuirrhand  Wasatch  ]\Iountains,  southwest  and 
southeast  of  Salt  Lake  City,  in  canons  well  up  toward  tlie 
summits.  The  region  is  much  disturbed,  and  there  are  great 
faults  and  porphyry  dikes  and  knobs  of  granite  associated  witL 
the  sedimentary  rocks.  The  ores  occur  in  belts,  extending  cou 
siderable  distances,  and  these  in  places  have  the  rich  chutes  or 
chinmeys  of  oxidized  products.  In  Bingham  Caiion  an  im- 
mense bed  of  auriferous  quartz  is  found,  overlying  the  lead 
zone  and  next  the  hanging.  Some  peculiarity  about  the  gold 
prevents  its  easy  treatment,  but  much  of  the  rock  is  very  low 
grade.  Recently  verj'  extensive  deposits  of  copper  ore  have 
been  found  in  the  Highland  Boy.  Other  fissure  veins  in  the 
massive  rock  of  the  region  are  known,  but  are  of  less  inqmrt- 
ance.  The  general  geological  relations  suggest  the  dept)sitH 
mentioned  under  Example  .30  and  subtypes.  The  mines  were 
the  occasion  of  the  first  development  of  tlie  lead-silver  smelters 
in  the  West,  and  have  made  Salt  Lake  City  an  important  ceii- 


'  J.  E.  Clayton,  "  The  C Vieur  d'Alene  Silver  lead  Jlines,"  /;//(/,  (ii"l  Min- 
Jour.,  February  11.  IHSH,  p.  lOS. 


ua  and 
(1  zone 
cciated 

wliicli 
s  are  in 
ortbern 
i,  much 
became 
iffovdcd 
liiderite. 

sources 
I  Paciiic 


\v 


ittle  Cot- 
coiitain- 
ite  below 
iderlyius 
mines  are 
iwest  and 
arci  the 
ire  'j^'veat 
ted  witli 
iiij^r  con- 
cbutes  or 
an  inv 
tbe  lead 
tbe  golil 
very  1*'W 
ore  bavc 
us  in  till' 
s  inijioi't- 
(lejiosit;^ 
ines  wt're 
r  smelters 
vtant  <'eii- 


n 


"fim^r 


-V,  te:  , 


fc»l- 


1  V  ,  . 
"*S  -t^    I, 


I       k 


►-       l^ 


,  -■■■■  -«*- 


.f-^ 


Fig.  9i).—Fteiy  0/ ifAe#o?(vi  (>/ .Vf<HiHi(>f/(,  Tiiific  district,  Utah.     From 
a  photoynqili  by  L.  E.  Ritcr,  Jr. ,  18'J8. 


Fia.  100.— Bullion  and  Beck  Mine  and  Mill,  Eureka,  Tintic  district,  Utah. 
From  a  photograph  by  L.  E.  Riier,  Jr.,  1898. 


LEAD  AND  SILVER. 


276 


^: 


From 


^.\% 


Id,  r/(('i. 


ter  of  the  industry.  Tho  Telegraph  group,  the  Emma,  Flag- 
staff, and  others  were  famous  mines  in  their  da)'.  As  will 
appear,  nearly  all  the  Utah  mines  are  productive  of  lead-silver 
ores. 

:.\(i8.24.  Example  ;i5a.  Tooele  County.  Bed  veins  in 
limestone,  or  between  it  and  cpmrtiiie,  and  containing  lead- 
silver  ores  with  others,  in  ri'*!)  chutes.  The  deposits  occur  in 
the  west  side  of  the  Oquirrh  range,  in  Ophir  and  Dry  canons, 
over  the  divide  from  Bingham.  Tiie  principal  mine  is  the 
Hoiioriue.  Fissure  veins  also  occur  i*:  the  region,  but  are  of 
less  importance.  The  Deep  Creek  district,  near  tho  Nevada 
line,  is  mentioned  under  '-i.  11.04.^ 

2.1)8.25.  Example  .■)")/>.  Tintic  District.  Ore  heds  or  belts, 
three  in  number,  and  one  to  three  miles  long,  generally  paral- 
lel with  the  stratification  of  vertical  blue  limestones,  but  some- 
times running  acrcjss  them.  Tiie  ore-bearing  zone  is  from  ;)(){)  to 
OdO  feet  wide  in  at  least  one  belt,  and  bears  in  places  rich  chutes 
of  cai  jonate  ore.  The  Crismon-Mammoth  has  been  referred  to 
under  "Copper"  (Example  2()r/),  as  it  contains  much  copper. 
The  ore  is  thought  bv  Hollister  to  have  replaced  the  limestone. "f, 

Passing  mention  should  also  be  made  that  lead-silver  ores 
occur  in  bummit  County,  at  the  Crescent  and  otiier  mines. 

'.\0S.2G.  Example  :5()f/.  Horn  Silver  Mi.. e,  Beaver  County. 
A  great  contact  fissure  between  a  rhyolite  hanging  wall  and  a 
limestone  footwall,  and  carrying,  at  the  Horn  Silver  mine, 
oxidized  lead-silver  ores,  chieiiy  auglesite,  with  considerable 


'W.P.Blake.  "Brief  Description  of  the  Fhiinia  Mine"  Amer.  Jour. 
Sci..  ii.,  II.,  2U}.  C.  E.  Feiiiier.  "The  Telej^raph  Mine,"  Schoui  of  Mhics 
QiKoicrly,  July,  ISfl:?.  O.  J.  Hollister,  "  (n)l<l  and  Silver  Mining  in  Utah," 
TniiiK.  Amer.  Iiist.  Mill.  Eiir/..  XVI.,  .3.  Kec.  1).  B.  Huntley,  Toith 
CniKiin.  Vol.  XIII,  p.  40r.  G.  LavaKnino,  "Tiie  Old  Telegrai)ii  Mine," 
Trails;,  .\iiicr.  /;/.s7.  Mill.  Eiuj..  XVI.,  '2.">.  "  Little  Cottonwood  and  Binf; 
liani,  Utah,"  Eiiij.  tiiid  Mhi.  Jour.,  .Antrust  i4,  ISMO,  p.  10(i;  also  .luly  Ii), 
18^!)  .[.  S.  Ne\vl)erry,  School  of  Mines  (Jiiiirlcrli/.  1SS|,  j).  :Vi\).  K.  W. 
Raymond,  Miiicnil  JicnoinrcN  Went  of  the  liocki/  Mountains,  18(18-76,  and 
J.  R.  Brown,  ll>i(t..  lS('.T-(iS  Ann.  Rrp.'i.  of  Director  of  the  Mint.  H.  Sil- 
liinau,  "(ieolofijical  and  Mineralogical  Notes  on  Some  Alining  Districts  of 
Utah,"  ..i„„T.  Jour.  Sci.,  in..  Ill  .  19".. 

'  I).  B.  Iluntlow  and  O.  J.  Hollister.  as  above,  under  last  footnote.  J. 
S.  Xewherry,  Encf.  and  Min.  Jour..  Septend)er  i:5  and '20,  18T9.  A  report 
on  the  district  is  in  press  with  the  U.  S.  CJeological  Survey. 


i'lC 


5j:g 


KKMP'8  OliE  DEPOSITS. 


barite,  and  with  many  other  rarer  minerals.  The  town  of 
FriHco,  containing  tlie  mine,  is  at  the  Houthern  end  of  the 
Grampian  Mountains.  The  great  tisaure  is  known  for  two  miles, 
but  is  proved  valuable  only  between  the  lines  of  the  Horn  Sil- 
ver mine.  It  strikes  north  and  south  and  dips  70°  east.  lu 
the  neighborhood  of  the  vein  the  rbjolite  is  largely  altered  to 
residual  clay.  The  mine  is  very  dry,  and  the  entire  region 
lacks  good  water.  The  vein  in  general  varies  from  20  to  (10 
feet,  but  has  pinched  twice  in  going  down,  and  of  late  years 
has  largely  ceased  producing,  although  there  may  yet  be  nnich 
ore  below.  The  ores  are  smelted  near  Salt  Lake,  and  the  bane 
bullion  is  refined  at  Chicago.  Some  free  milling  ore  has  been 
afforded.' 

2. OS. 27.  Example  XUi.  Carbonate  Mine,  Beaver  County. 
A  fissure  vein  in  hornblende  andesite,  filled  with  rounded  fra;;- 
n)ents  of  wallrock,  which  are  cemented  by  residual  clay  ami 
galena.  Some  oxidized  lu'oducts  occur  near  the  surface.  The 
mines  are  two  and  a  half  miles  northeast  of  Frisco,  but  are  in 
a  different  eruptive  rock  from  that  forming  the  walls  of  the 
Horn  Silver.  The  literature  is  the  same  as  for  Example  'M)g, 
especially  Hooker,  1.  c.  p.  470. 

2.0S.2H  Example  ;52/>.  Cave  Mine,  Beaver  County.  Cham- 
bers irregularly  distributed  in  the  limestone,  and  more  or  less 
filled  with  limonite  and  oxidized  lead-silver  ores.  Small  lead- 
ers of  ores,  which  mark  old  conduits,  connect  the  chambers. 
Up  to  18S0  five  large  and  fifteen  small  chambers  had  been 
found.  They  are  of  very  irregular  shape,  and  have  a  vacant 
space  of  from  one  to  ten  feet  between  tlie  ore  and  the  roof. 
This  deposit  was  the  typical  one  cited  by  Newberry  as  illustrat- 
ing the  chamber  or  cave  form  of  deposit.  According  to  this 
view,  the  chambers  were  formed  l)efore  the  ore  was  brought  in. 

It  is  also  possible  that  the  ore  bodies  have  been  deposited  l)y 
replacement  of  the  limestone  with  sulphides,  as  is  known  abuu- 
dantly  elsewhere,  and  that  the  alteration  of  these  to  oxides  has 
occasioned  the  apparent  caves.  The  products  of  the  niino 
afford  but  5  to  7%  lead,  but  are  valunble  as  an  iron  flux  to  the 

•  O.  J.  Ilollister,  "  GoUl  and  Silver  Mining  in  Utah,"  Tram.  Amcr.  Inst- 
Min.Eiig.,  XVI.,  3.  Rec  W.  A  Hooker,  Report  quoted  in  the  Tcnih 
Census,  Vol.  XIII.,  p.  401. 


LEAD  AND  S/LVKH. 


277 


;own  <»f 

of  tbe 
ro  mill's, 
[orn  Sil- 
liiat.  In 
.Itered  to 
e  region 

20  to  »iO 

ate  years 

be  nnicli 

I  the  Inline 

I  has  been 

r  County, 
ailed  fra^- 

clay  anil 
ace.     The 

but  are  in 
ills  of  the 
^niple  -Wg, 

y.  Cbiini- 
love  or  loss 
nmll  lead- 
cbanibers. 
hail  been 
re  a  vacant 
1  the  roof. 
IS  illustrat- 
ing to  tliis 
rouglit  in. 
posited  liy 
own  abuu" 
oxiilt's  li!>^ 
the  wine 
flux  to  the 

Amcr.  Iiisf. 
liu  the  Tenth 


ut'ighhoring  smelters.     The  mines  are  iu   the  Qrauite  range, 
seven  miles  southeast  of  Mil  ford.' 

Note. — Although  the  larger  part  of  the  Utah  mines  are  for 
lead  and  silver,  several  others  of  great  importance  will  be  taken 
lip  under  "Silver"  itself. 

NEVADA. 

2.08.20.     Example  W.     Eureka.     Bodies  of  oxidized  lead- 
silver  ores  in  much  faulted  and  fractured  Cambrifiu  limestone, 
with  great  outbreaks  of  eruptive  rocks  near.     The  P]ureka  goo 
Ittgical  section  is  one  of  the  most  interesting  in  the  entire  coun- 
try, and  involves  some  ;K),0()0  feet  of  Paleozoic  strata,  divided 
as  follows;  Cambrian  ipiartzite,  limestone,   and    shale,  7,700 
feet;  Silurian   limestone  and    (juarztite,  .'),()()()    feet;  Devonian 
limestone  and  shale,  S,()(H)feet;  Carboniferous  (juartzite,  lime- 
stone, and  conglomerate,  It, :{()(•  feet.    These  have  ati'orded  some 
extremely   valuable  materials   for  comparative  studies   with 
liomotaxiai  strata  in  the   East.     The  ore  occurs  especially  in 
wliat  is  called  the  Prospect  Mountain    limestone  of  the  Cam- 
brian, one  smaller  deposit  being  also  known  in  Silurian  (puirtz- 
ito.     The  limestone  has   been   crushed  and  shattered  along  a 
great  fault,  and  through  its  substance  ore  solutions  have  circu- 
lated, replacing  it  in  part  with  large  bodies  of  sulphides  which 
have  afterward  become  oxidized    to  a  depth  of  1,000  feet.     The 
ore  bodies  were  puzzling  as  regards  their  classilication,  and  a 
famous  mining  suit,  with   many  interpretations  from    various 
experts,  resulted.     The  alteration  of  the  ore  has  caused  shrink- 
afj;e,  and  the  formation  of  apparent  caves  over  it.     But  there 
are  many  empty  caves,  formed  by  surface  waters  long  after  the 
ore  was  deposited,  and  J.  S.  Curtis  very  clearly  shows  that  the 
ore  bodies  originated  by  replacement.     All  are  connected  with 
more  or  less  strongly  marked  fissures  which  formed  the  con- 
duits.    Mr.  Curtis  made  a  careful  series  of  assays  of  the  neigh- 
boring igneous  rocks  to  find  some  indication    of  the  source  of 
the  ore.     A  quartz  porphyry  gave  significant  results,  and  to 
this  the  metals  are  referred,  the  portions  of  the  mass  at  a  great 

'  0.  J.  HoUister,  "Gold  and  Silver  ^lining  in  Utah,"  Trans.  Amer.  Innt. 
Mill  Eiuj.,  XVI.,  3.  D.  B.  Huntley.  Tenth  Census.  Vol.  XllI  ,  p.  4T-1.  J. 
S  Xewherry,  School  of  Mines  Quarter! i/.  Marcli.  ISSO.  Keprint,  p.  !).  Cf. 
also  ,1.  B.  Kimball.  "The  Silver  Mines  of  Eulalia,  Chihuahua,"  Amer. 
Jour.  Sei.,  ii.,  XLIX..  161. 


II 


2:8 


hhMI'S  oniC  DEPOSITS. 


depth  are  considored  to  have  furuished  them.  Eureka  wuh 
oue  of  the  HrHt  phiceH  in  tliis  country  where  the  hypothsHis  of 
rephu'enient  was  applied  to  ores  in  limestone.  The  district  is 
now  far  less  productive  than  it  waa  fifteen  or  twenty  years  ago.' 


Flu.  101. — Section  at  Eureka,  Nev.     Reproduced  in  line  work  after  colored 
plate  by  J.  S.  Curtix,  Monoyraph  VI.,  U.  S.  Oeol.  Survey. 

'  G.  F.  Becker.  Tenth  Cphsuh,  Vol.  XIII.,  p  32.  Rec.  W.  P.  Blake, 
"The  Ore  Deposits  of  the  Eureka  District,  Nevjida,"  Trans.  Amer.  Just. 
Mill.  Eit;/..  VI.,  r)ri4.  .J.  S  Curtis,  "Silver-lead  Ore  Deposits  of  Eurpka, 
"Nev.,"  AIoiKH/raph  VII. ,  U.  8.  Geol.  Survey.  A.  Hague,  "  Geology  of  the 
Eiu-eka  District,"  Monograph  XX.,  U.S.  Geol  Survey.  Abstract  in  Third 
Ann.  Rep.  Direetor  U.  S.  Geol.  Surveg.  W.  S.  Keyes,  "Eureka  Lode  of 
Eureka,  Nev.,"  Trans.  Anier.  In.st.  Min.  Eiig.,  VI.,  344.  J.  S.  Newberry, 
School  of  Mines  Quarterly,  March,  18Mn.  R.  W,  Raymond,  "The  Eureka- 
Rifhinond  Case,"  Trans.  Amer.  Inst.  Min.  Eng.,  VI.,  371.  C.  D.  Walcott, 
•Paleontology  of  the  Eureka  District,"  Monograph  VIII.,  U.  S.  Oeol. 
Survey. 


cft  was 
jeniH  of 
strict  is 
Tsago.' 


LKAD  AND  SILVKH. 


ARIZONA— CALIFOKNIA. 


279 


*ll 


•i.08.:U>.  Comparatively  small  amouuts  of  lead  ores  are  wliip- 
pcd  from  Arizona  from  time  to  time,  chieMy  from  C<x;lii8e 
C!()iinty  (Tombstone  roj^ion)  and  Pima  County  (Tucson  region). 
They  will  be  mentiont'd  under  "Silver."  Insignificant  amounts 
an-  also  afforded  by  California  (about  $*2, ()()(»  in  1SK'.»),  mostly 
from  Inyo  County.  (See  Eleventh  Census^  Bull.  No.  80,  June 
IS,  18'Ji.) 


■I  ciiiroii 


Ml 


CHAPTER  IX. 

SILVER   AND   GOLD.— INTRODUCTORY  :   EASTERN   SILVER   MINES 

AND     THE     ROCKY     MOUNTAIN    REGION    OF    NEW 

MEXICO   AND   COLORADO. 

2.0t).01.  The  two  "precious"  metals  are  so  genera uy  asso- 
ciated that  they  cannot  be  separately  treated.  While  endeav- 
oring to  preserve  the  distinctive  impression  given  by  examples, 
it  is  practically  impossible  to  set  forth  all  the  widely  varying 
phenomena  of  the  silver-gold  veins  of  the  West  in  any  other 
than  an  approximate  way.  Hence  geographical  considerations 
are  placed  first  and  where  markedly  similar  ore  bodies  in  dif- 
ferent States  are  to  be  grouped  together  cross  references  are 
given.  The  following  general  examples  have  been  made  be- 
cause their  individual  features  are  based  on  those  geological 
relations  which  are  most  vitally  concerned  with  ([uestions  of 
origin. 

2.0'.).0'^.  Example  oT.  Veins  containing  the  precious  met- 
als usually  with  pyrite,  galena,  chalcopyrite,  and  less  common 
sulphides,  sulpharsenules,  sulphantinionides,  etc.,  in  igneous 
rocks.  No  special  subdivision  is  made  on  the  character  of  the 
gangue,  which  may  be  quartz,  calcite,  barite,  fluorite,  etc.,  one 
or  all.  The  first  naiheil  is  commonest.  A  great  and  well- 
defined  original  fissure  is  not  necessarily  assumed,  but  some 
crack,  or  joint  or  crushed  strip  must  have  directed  the  ore- 
bearing  solutions,  which  may  have  then  replaced  the  walls  iu 
large  measure.  For  other  structural  features  see  the  discussion 
of  veins  (1.0,5. 01);  compare  also  Example  17,  Butte,  Mont. 

Example  37a.  Replacements  more  or  less  complete  of 
igneous  dikes,  which  have  usually  been  described  as  porphyry. 
Compare  Example  l.'(t  under  "Copper"  (Gilpin  County,  Colo- 
rado), and  Example  "iOf/  (Santa  Rita,  N.  ]\I.).  ( )re  and  gangue. 
where  the  matrix  is  not  the  dike  rock,  as  in  Example  37. 


SILVEP  AND  GOLD.  281 

Example  38.  CoDtact  deposits  between  two  kiuds  of  igneous 
rock  or  between  two  different  flows.  Ore  and  gangue  as  in 
Example  37. 

Example  39.  Agglomerates  of  rounded,  eruptive  boulders, 
bombs,  etc.,  in  abandoned  volcanic  necks  or  conduits,  and 
coated  with  ores.  The  Bassick  mine  of  Cueter  County,  Colo- 
rado, is  tbe  only  example  of  an  ore  deposit  of  tbis  kind  yet 
identified. 

Example  40.  Contact  deposits  between  igneous  and  sedi- 
mentary rocks.  No  subdivisions  are  made  on  tbe  kind  of  rocks. 
Ore  and  gangue  as  in  Example  37.  Tbe  ore  body  may  replace  a 
calcareous  rock  along  tbe  under  side  of  an  intruded  sbeet.  Com- 
pare also  Example  ;2(),  "Arizona  Cojiper" ;  Example  'i\a, 
"Triassic  Copper";  Example  30,  "Leadville";  anJ  Example 
30g,  "Horn  Silver  Mine." 

Example  41.  Veins  in  sedimentary  rocks,  generally  cutting 
tbe  bedding,  but  at  timesLi  parallel  witb  it.  Lateral  enlarge- 
ments are  frequent.  Tbe  ore  body  may  be  largely  due  to  tiie 
replacement  of  some  calcareous  rock,  sucb  as  limestone  or  lime- 
sbales,  beneatb  some  relatively  impervious  bed.  Ore  and  gan- 
gue as  in  Example  37. 

Example  42.  Veins  cutting  botb  sedimentary  and  ^'gneous 
rocks,  and  tberefore  due  to  disturbances  after  tbe  intrusion  of 
tbe  latter.     Ore  and  gangue  as  in  Example  37. 

No  special  examples  are  made  for  metamoi  pbic  rocks. 

2.09.03.  Minerals  containing  silver  or  gold. 

Ag.  S.         As.        Sb.          CI. 

X;itive  silver 100 

Ar<;enite  (Sliver  ^laiu'e),  Ag^S 87.1     12.9     

i'niusite  (liglit  ruby  silver),  ^Ag^S.As.Sg,.  B5..'}     19.4    V)l     

ryiiirgerite  (dark  ruby  silver),  3AgoS.SboS,,  (10.       17.8     22.2     

Stephiinite  (brittle  .silver),  oAgoS.SbgSj.  ..  .  (iH.T)     1(5.2     ....     1.5.3     

Cerargerite  (born  silver),  AgCl 7,5.3     24.7 

Silver  also  occurs  witb  galena  (Cf."Lead")  and  witb  tetra- 
bedrite  (Cf.  "Copper").  Gold  (X*curs  combined  witb  tellu- 
rium in  tellurides;  mecbanically  mingled  witb  pyrites;  and  as 
tbe  uncombined  native  metal.  From  a  metallurgical  point  of 
view  rbe  ores  of  tbe  precious  metals  are  divided  into  two 
•  'lasses.  1.  Tbose  who.se  amount  of  precious  metal  amalga- 
mates readily  witb  quicksilver,  and  is  tbus  obtained  witb  com- 


■ 


382 


KKMP'S  OJiE  DEPOSITS. 


parative  ease — the  free  milling  ores,  2.  Those  which  re(]iiire 
roasting  or  some  previous  treatment  before  amalgamation, 
chlorination,  or  similar  process,  or  which  must  be-  smelted  pri- 
marily for  lead  or  copper,  from  which  the  precious  metals  are 
afterward  extracted — the  rebellious  ores.  In  the  subset juent 
description  the  endeavor  has  been  made  to  work  from  the  dis- 
tinctively silver  mines  to  those  of  gold,  where  geographically 
possible.' 

The  precious  metals  seem  to  have  been  derived  in  almost  all 
cases  from  deep-seated  sources,  and  presumably  from  igneous 
rocks,  even  though  they  may  now  be  found  in  sediments  or 
metamorphic  rocks.  The  valuable  and  thorough  researches  of 
J.  R.  Don  upon  the  Australian  gold-bearing  reefs,  the  neigh  bor- 
ing wall  rocks,  and  the  sea  water  as  a  possible  source  of  the 
precious  metal  have  led  to  increased  faith  in  its  derivation  by 
uprising  solutions.     Both  Blake  and  Merrill  have  discovered 


'  Ann.  R('}M.  Dircvtoi\s  of  the  Mint.  Pro  W.  P.  Blake,  "  The  Various 
P'orins  iu  whicli  (Jokl  Occurs  in  Nature."  Rep.  Director  of  Ihe  Mint,  1SS4, 
p.  578.  Rec.  '•  Gold  iu  Granite  aud  Plutonic  Rocks,"  Trans.  Amer.  Inst. 
Mia.  En(i.,  XXVI.,  '2!)(),  ISiKI.  Brown.  Raymond,  and  others.  1808  to  IHTO, 
"Mineral  Resources  West  of  the  Rocky  Mountains.'  Annual.  T.  C. 
Chamberlin,  "On  the  Geological  Distribution  of  Argentiferous  Galena," 
Geol.  of  nV.s.,  Vol.  IV.  Cunienge  and  Robellaz.  "LOr  dans  la  Nature." 
Paris,  IHTi).  L.  De  Lauuay,  "Contribution  a  I'etude  des  Gites  Metal 
U{(;res,  Annates  (Ics  Mines,  August,  1897,  108.  J.  R.  Don,  "The  (jene.sis 
of  Certain  Auriferous  Lodes,"  Trans.  Amer.  Inst.  Min.  Eng.,  XXVII.,  oW, 
18!)7.  Rec.  .1.  F.  Kenii\  "Geological  Occurrence  and  A.ssociates  of  the 
TellurideGoldOre.s,"  The  Mineral  Imliistri/,  VI.,  29r)-;!3(»,  181)8.  Clarence 
King.  "  Production  of  the  Precious  Metals  in  tiie  United  States,"  6Vco»f^ 
Ann.  Rep.  Director  U.  S.  Geol.  Survey,  p.  ii'Ali.  A.  G.  I.o(^k,  Gold,  1882.  (i. 
P.  Merrill,  "Gold  in  Granite,"  Anier.  Jour,  of  Sci.,  x\pril,  18i)(),  IWd.  Mineral 
Resources  of  the  U.  S.;  annual  publication  of  the  Geological  Survey.  R 
I.  ]\Iurchison,  "General  View  of  the  Conditions  undei  wliich  Gold  is  Dis 
tributed,"  (Juar.  Jour.  Geol.  Soc,  VII.,  184.  Also  in  Siluria  and  Aincr. 
Jour.  Sci.,  ii.,  XV' III.  301.  J.  S.  Newberry,  "On  the  Genesis  and  Distri- 
bution of  Gold,"  School  of  Mines  Quarterli/.  III.,  No.  1,  and  Eng.  and  Min. 
Jour..  December  24  and  81,  1881,  pp.  41(],  487.  R.  Pearce,  "  On  the  Ores 
of  Gold. "etc.,  Colo.  Sci.  Soc,  III.,  p.  287.  J.  A.  Phillips,  Ore  Deposils. 
1884.  The  Mining  and  Metallurgy  of  Gold  and  Silver,  18(17.  Tenth  Cen- 
sus Refiort  on  the  Precious  Melals.  Albert  Williams.  "  I'opular  Fallacies 
Regarding  Precious  Metal  Ore  Deposits,"  Fourth  Aru.  Rep.  Dir.  U.  S. 
Geol.  Survey,  1884.  J.  H.  I .  Vogt,  Zeitschrift  fi'ir  prakt.  Geologic,  Scii 
tember,  1898,  821.  "Ueber  die  Bildung  des  Gediegen  Silbers,"  etc.,  Idem. 
April,  1899,  118. 


SILVER  AND   GOLD. 


283 


gold  in  granite,  and  Moricke,  as  earlier  cited,  1,01}. 06,  observed  it 
in  obsidian. 

2.00.04.  Example  "Z'la.  Atlantic  Border.  Already  men- 
tioned (2.05.0'^),  the  region  is  onlj-  of  historical  interest  as  af- 
fording silver,  although  lately  some  attention  has  been  directed 
to  Sullivan,  Me.,  where  the  veins  have  pyrite  and  probably 
stephanite,  in  a  (juartz  gangue,  in  slates,  associated  with  gran- 
ite knobs  and  trap  dikes,  which  are  of  later  age  than  the  veins. 
Some  silver  is  generally  found  in  the  galena  of  the  Eastern 
States,  but  the  ores  have  never  yet  proved  abundant  enough  to 
be  important.^ 

Mention  may  also  be  n\B,i^^  at  this  point  of  the  argentiferous 
galena  veins  along  the  Ouachita  uplift  of  Arkansas.  A  few 
are  known,  usually  with  Trenton  shales  or  slates  for  walls. 
They  are  low  grade,  and  though  o:)ce  the  basis  of  a  small  ex- 
citement, their  production  has  never  been  serious.  Additional 
reference  to  the  region  will  be  found  under  "Antimony." 
Some  mines  of  the  latter  metal  are  stated  by  W.  P.  Jenney  to 
show  low-grade,  argentiferous  ores  in  depth." 

2.09.05.  Example  42.  Silver  Islet,  Lake  Sujjerior.  A 
fissure  vein  carrying  native  silver,  argentite,  tetrahedrite, 
galena,  blende,  and  some  nickel  and  cobalt  compounds  in  a 
gangue  of  calcite,  in  flags  and  shales  of  the  Animikie  (Algon- 
kian)  system,  and  cutting  a  large  trap  dike,  within  which 
alone  the  vein  is  productive.  Silver  Islet  is  or  was  originally 
httle  more  than  a  bare  rock  some  W  feet  square,  lying  off  the 
north  shore  of  Lake  Superior  just  outside  of  Thun:ler  Bay,  and 
within  the  Canadian  boundaries.  The  native  silver  was  de- 
tected outcropping  beneath  the  water.  The  vein  wai  produc- 
tive to  a  depth  of  SOO  or  1, (»(»()  feet,  but  below  this  it  yielded  lit- 
tle. The  trap  dike  has  usuallj'  been  called  diorite,  but  is  deter- 
mined to  be  norite  by  Wadsworth  {Bull.  3,  Minn.  Oeol.  Sur- 
reij,  p.  92),  and  gabbro  by  Irving  (Monograph  T'.,  U.  S.  Geol. 


'  C.  W.  Kemptoii,  "Sketches  of  the  New  Mining  District  at  Snllivan, 

Me.,"   Trans.    Aiiwi'.    Inst.    Min.    En<f.,   VII.,    ;{4S».      M.    K.    Wadswortli, 

■Theories  of  Ore  Deposits."   Proc.  Boston    Soc.  Nat.   Hist.,  1S,S4,  p.  i»()5. 

Eufi.   and  Min.  Jour.,  May  IT,   1HS4.     Bnll.   Mus.  (^nmi).  Zool.   ^,   Vol. 

VII.,  LSI. 

'T.  B.   (^omstock,  Ann.  Rep.   Oeol.   Survey  of  Arkansas,    1888,  Vol.  I., 
"Gold  and  Silver." 


284 


KEMP'S  ORE  DEPOSITS. 


Survey,  p.  378).  Some  $;3,()()(),0()()  were  obtained  from  the 
miue,  yet  the  expenses  were  so  great  in  keeping  up  the  surface 
works  against  winter  gales  and  ice  that  but  little  profit  was 
realized.  The  vein  has  been  traced  0,{)()()  feet,  but  is  nowhere 
else  productive.  Considerable  graphite  has  been  found  in  the 
workings,  and  some  curious  pockets  of  gas.^ 

2.00.0G.  Example  42.  Thunder  Bay,  Canada.  The  main- 
land near  Silver  Islet  contains  many  similai  eins.  They  have 
furnished  considerable  silver,  as  argentit.  in  a  gangue  of 
quartz,  barite,  calcite  and  fluorite,  and  associated  with  zinc- 
blende,  galena,  and  pyrite.* 

THE  RE(iION  OF  THE  ROCKY  MOUNTAINS  AND  BLACK  HILLS. 

NEW   MEXICO. 

2.09.07.  Geoloqij. — The  general  topography  and  geology  of 
New  Mexico  were  outlined  in  the  introduction.  Much  remains 
to  be  done  in  developing  its  geology.  The  eastern  part  belongs 
to  the  prairie  region,  and  is  very  dry.  A  few  rivers,  notably 
the  Pecos  and  the  Rio  Grande,  afford  water  for  irrigation,  the 
former  of  which  is  now  being  utilized  on  a  grand  scale,  and  for 
the  latter  pl.ns  have  been  prepared.  In  the  central  portion  many 
subordinate  north  and  south  ranges  of  mountains  are  found, 
which  are  less  elevated  than  those  of  Colorado,  The  Colorado 
ranges  virtually  die  out  at  the  northern  boundary.  The  north- 
western portion  comes  in  the  great  Colorado  plateau,  and  has 
been  quite  fullj  described  by  Captain  Dutton  {Eighth  Ann. 
Rep.  Director   U.  S.  Geol.  Surveif).     In  numerous  localities 

'  R.  Bell,  Eiig.  and  Min.  Join:,  January  H  and  15,    18^7.     See  also  May 

14,  1887.  W.  M.  Courtis,  "  Ou  Silver  Lslet,"  Eiiy.  and  Miu.  Jour.,  Decem- 
ber '2\,  1873,  and  Trans.  Amer.  last.  Min.  Eng.,  V..  474.  E.  D.  luKall. 
Ann.  Ri'p.  Can.  Geol  Surrey,  1887-88,  Part  II.,  p.  14.  F.  A.  Lowe,  "Tlie 
Silver  Islet  Mine  and  its  Present  Development,"  Eng.  and  j\Hn.  Jour., 
Deeeni>)er  1(5,  1882.  p.  321.  T.  MacFarlaue,  'Silver  Islet,'  Tran.'^.  Anicr. 
Inst.  3Iin.  Eng.,  VIJI.,  226.  Geol.  of  Canada,  1863,  717.  Canadian  Nat 
uxdi.'^f.  Vol.  IV.,  p.  37.  McDermott,  Eng.  and  Min.  Jour.,  Vol.  XXIII., 
Nos.  4  and  5. 

'  R.  Bell,  "Silver  Mines  of  Thunder  Bay,"  Eng.  and  Min.  Jour.,  Jan 
uary  8  and  1,1,  1887.  E.  D.  Ingall,  Ann.  Rep.  Can.  Surrey,  1887-88,  Part 
II.,  p.  lU.     Rec.     See  also  Eng.  and  Min.  Jour.,  May  14,  1887:  February 

15,  1888.  p.  133;  May  26,  1888,  p.  383.  W.  M.  Courtis,  "Aniniikie  Rocks 
antl  their  Vein-phenomena  as  shown  at  the  Duncan  Mine,"  Trans.  Anwr. 
Inst.  Min.  Eng.,  XV.,  671;  see  also  V.,  473. 


SILVER  AND  GOLD. 


ilso  May 
Decern- 
liif^iill. 
,   "TIk' 

H.  Jo((/-., 

(IH  Nitt- 

XXIII.. 


285 


throughout  the  Territory  volcanic  action  has  been  rife,  and  in 
places  is  but  recently  extinct.  The  eastern  part  is  largely  Cre- 
taceous, and  also  the  northwestern  plateau,  which  contains 
much  valuable  coal.  The  mountain  ranges  often  have  nuclei 
of  Archean  crystalline  rocks,  with  successive  strata  of  Carbon- 
iferous, Permian,  Triassic,  Jurassic  and  Cretaceous  on  the 
Hanks.  The  mining  regions  are  in  these  ranges  of  mountains.' 
2.00.08.  The  southwestern  county  is  Grant,  whose  lead- 
silver  deposits  have  been  briefly  referred  to.  North  of  Silver 
City  are  quartz  veins  of  gold  and  silver  ores,  in  diabase  and 
quartz  porphyry  (Example  o7),  and  again,  west  of  Silver  City, 
are  ferruginous  deposits  with  chlorides  and  sulphides  of  silver 
in  limestone.  In  the  Burro  Mountains  are  silver  ores  in  lime- 
stones, apparently  Lower  Silurian.  The  Santa  Rita  Mountains 
contain,  in  addition  to  the  copper  (Example  iOd),  silver  and 
gold  in  quartz  veins  in  eruptive  rocks  (Example  157).  Lake 
Valley,  in  Dona  Aiia  County,  has  been  mentioned  (:2.()<S.04). 
In  Lincoln  County  gold  ores  are  reported  from  the  White  Oak 
district.     The   princi{)al   mines  of  Socorro   County  have   been 

'  W.  P.  Blake,  Proc.  Host.  Soc.  Nat.  Hiftf.,  185!),  Vol.  VII.,  p  64.  "Ce- 
oloj^y  of  tlie  Rocky  Mountains  in  the  Vicinity  of  Santa  Fe,"  Aincr.  Asuo. 
Adv.  Sci.,  1859.  A.  R.  Conkliiig,  "  Rej^rt  on  Certain  Foothills  in  North- 
ern New  Mexico,"  Wheelers  Survey.  Rep.  of  Chief  of  U.  S.  Euijhieeva, 
1877,  II.,  l-^!»8.  E.  D.  Cope,  "Report  on  the  (ieology  of  a  Part  of  New 
Mexico,"  Wheeler's  Survey,  1875;  Appendix  Gl.  C.  E.  Dntton,  "Mount 
Taylor  and  the  Zuni  Plateau,"  Sivih  A}i)i.  Rep.  U.  S.  Geol.  Survey,  pp. 
IU-205.  S.  F.  Emmons,  Tenth  Census.  Vol.  XIII.,  100.  O.  Loew,  'Re- 
jKirt  on  the  Geology  and  Mineralogy  of  Colorado  and  New  Jlex'co  ' 
Wheeler  s  Survey.  1875;  Appendix  G'i.  p.  27.  J.  Marcon,  "The  Meso/oio 
Series  of  New  Mexico,"  Anter.  Geol.  IV.,  155,  21().  R.  E.  Owen  and  E.  J. 
('o.\,  "Report  on  tlie  IMines  of  New  Jlexico,"  Washington.  ISC)."),  (SO  pp., 
Ainer.  Jour.  Sci.,  ii.,  XL.,  301.  G.  F.  Rujiton.  "On  the  Volcanic  Rocks 
of  New  Mexico,"  Quar  Jour  Geol.  Soe..  Vol.  VI.,  p.  251,  18.50.  B.  Silli- 
iiiiiii.  ,Tr..  "The  Mineral  Regions  of  Southern  New  Mexico,"  Trans  ^{nier. 
lux/.  Mill.  Eug.,  X.,  424.  F.  Springer,  "  Oecun'ence  of  the  Lower  Burling- 
ton Limestone  in  New  Mexico,"  Anier.  Jour.  Sri ,  iii..  XXVII..  OT.  J.  ,1. 
Stevenson.  "  (leological  Examinations  in  Southern  Colorado  and  North- 
ern New  Mexico,"  ^Vlieeler's  Survey,  1881.  "Geology  of  (lalisteo Creek," 
Amcr.  Jour.  Sci.,  iii.,  XVIIL,  471.  "  On  the  Laramie  Group  of  Southern 
New  Mexico,"  Atuer.  Jour.  S''i.,  iii.,  XXIL,  ;rO.  For  the  Hihliograpiiy  of 
the  Geology  of  the  Territory  in  general,  see  Bulletin  of  the  V.  S.  Geol. 
Survey.  137  (literature  up  through  IsiH) :  l:.(l  (1.8<)2-18!);{) ;  135  (1894); 
146  (181).^) :  149  (189!i) :  1.56  (189:),  and  annual  issues. 


I 


286 


KhJMP'S  QUE  DEPOSITS. 


mentioned  (Example  2'.»),  and  the  copper  in  Permian  sandstone 
under  Example  'l\c.  There  are  other  silver-bearing  lodes  in 
the  Socorro  Mountains  near  the  town  of  Socorro.  Henrich  has 
described  (1.  c.)  a  curious  deposit  of  quartz  carrying  gold  and 
silver  (the  Slayback  Lode)  on  the  contact  between  the  older 
bedded  eruptions  and  a  later  siliceous  dike  in  the  Mogollou 
range  (Example  J5S).  In  Santa  Fe  County  are  important  placer 
mines  (Example  44)  and  thin  veins  of  galena  in  rhyolite.  In 
Bernalillo  County  are  placers  on  the  slopes  of  the  Sandia 
Mounfeiins.  In  Colfax  County,  in  the  Rocky  Mountains,  are 
other  placers,  and  reported  gold  and  silver  mines.* 

COLORADO. 

2.00.00.  Geology. — The  eastern  portion  contains  plains 
and  is  a  region  lacking  water.  It  consists  of  Quarternary  and 
Cretaceous  rocks.  The  plains  rise  in  the  foothills,  which  are 
chiefly  upturned  Jura-Triassic  and  Cretaceous  strata.  The 
Paleozoic  is  relatively  limited,  although  known.  It  rests  on 
the  crystalline  rocks  of  the  Archean.  There  are  some  minor 
uplifts,  running  out  at  right  angles  to  the  Front  range,  that 
divide  the  foothill  country  into  basins,  and  are  especially 
important  in  connection  with  coal.  Next  come  the  easterly 
ranges  of  the  Rocky  Mountains,  in  linear  north  and  south 
succession.  They  consist  largely  of  dome-shaped  peaks  of 
granite,  with  great  local  developments  of  volcanic  rocks.  To 
the  west  follow  the  several  parks,  chiefly  consisting  of  Meso- 
zoic  strata.  They  are  bounded  by  ranges  again  on  the  west, 
some  of  wliich,  like  the  Mosquito  range  (see  under  Example  30), 
mark  great  lines  of  post- Cretaceous  upheaval,  and  are  accom- 
panied by  inmiense  igneous  intrusions.  On  the  east  and  west 
flanks  of  the  Sawatch  range  (the  granitic  Continental  Divide) 
are  Paleozoic  strata  in  considerable  thickness,  but  to  the  west 

'  W.  P.  Blake,  "Gold  in  New  Jlexico,"  Proc.  Bost.  Soc.  Nat.  Hisf.. 
VII.,  p.  16,  July,  IHoO.  "Observations  on  the  Geology,  etc.,  near  Kauta 
Fe,"  Amer.  Afiso.  Adr.  of  Si-i..  XIII.,  314,  18(51).  S.  F.  Emmons,  Tetith 
Cen.'iK.'i.  XIII.,  p.  101.  C.  Ilenricli.  "The  Slayback  Lode,  New  Mexico,' 
Eng.  ami  Miii.  Jour.,  July  i:5,  188!),  p.  27.  R.  E.  Owen  and  E.  T.  Co.v, 
Rep.  on  the  Mines  of  New  Mexico,  Washington,  186.").  Pep.  Director  of  the 
Mint.  1882,  p.  :^:19.  B.  Sillinian,  "IMineral  Resources  of  Southern  New 
Mexico,"  Traits.  Amer.  In.^it.  Min.  Eny.,  X.,  424.  Eng.  and  Min.  Jour., 
October  14  and  21,  1883,  pp.  199,  212. 


ISILVER  AND  GOLD. 


287 


they  (lip  under  tlie  vastly  greater  development  of  Mesozoic  ter- 
ranes,  which  shade  out  into  the  Colorado  plateau.  In  northern, 
central  and  southwestern  Colorado  are  vast  developments  of 
igneous  rocks  that  have  attended  the  geological  disturbances.' 
2.0i>.10.  The  San  Juan  region  includes  several  coimties  in 
southwestern  Colorado,  in  whole  or  in  part,  viz. :  Ouray,  Hins- 
dale, San  Juan,  Dolores,  and  La  Plata.  The  chain  of  the  San 
Juan  Moimtaius  consists  of  great  successive  outflows  of  erup- 
tive rocks,  audesite,  diabase,  diorite,  basalt,  etc.,  which  cover 
up  the  Archean  and  later  sedimentary  terranes,  except  in  a 
few  scattered  exposures.  Considerable  masses  of  rocks  formed 
of  fragmental  ejectamenta  are  also  known.  All  these  are  crossed 
by  immense  vertical  veins,  largely  with  quartz  gangue,  and  con- 
taining argentiferous  minerals  of  the  usual  species,  galena, 
tetrahedrite,  pyrargerite,  and  native  silver,  as  well  as  bisnnith 
compounds.  Gold  has  been  quite  subordinate,  although  late 
developments  near  Ouray  have  shown  some  peculiar  and  inter- 
esting deposits.  R.  C.  Hills,  as  quoted  by  S.  F.  Emmons,  ISSo, 
traced  three  systems  of  veins.  (1)  Silver  beariug,  narrow  (six 
inches  to  three  feet),  nearly  vertical  veins,  with  base  metal  ores 


•  G.  L.  Cunnon,  " Quaternary  of  tlie  Denver  Basin,"  Pvov.  ('nlo.Sci. 
Soc,  III.,  4S.  See  also  HI.,  2llO.  "(JeoloKy  of  Denver  and  Vicinity," 
Idem,  IV.,  235.  Rec.  W.  Cross,  "Tlie  Denver  Tertiary  Formation," 
Amer.  Jonr.  Sci.,  iii.,  XXXVII..  2()l.  'Pike's  Peak,"  Atlas  Folio, 
V  S.  Geol.  Snrivy,  No.  7.  Rec.  "On  a  Series  of  Peculiar  Schi.sts  near 
Salida,"  Proc.  Colo.  Sci.  Soc,  IV.,  2S(!.  Rec.  "The  Laccolitic  Mtn. 
(ironjis  of  Colorailo.  Utah  and  Arizona,"  ^■Djjf.  Rcj).  Dir.  U.  S.  dcnl.  Siir- 
rci/.  XIV.,  1  (')■").  Rec.  U.  H.  Eldred^e,  "On  the  Country  about  Denver, 
Colo.,"  Proi:  Colo.  Sri.  Soc,  III..  S().  See  also  140.  S.  F.  Emmons, 
'•Orograi>hic  ^Movements  in  the  Rocky  Mountains, "  Geol.  Soc.  of  America, 
I,,  24.-)-2H().  F.  :M.  Endlich,  "On  the  Eruptive  Rocks  of  Colorado."  IViith 
Aim.  Pep.,  Ildi/ih'ii's  Siirrri/.  II.  (iannett,  "Report  on  the  Arable  and 
Pasture  Laiuls  of  Coloratlo,"  Haijdcii'n  Sitrvcif,  lST(i,  )).  !5i;!.  11.  C.  Free 
man,  "The  La  Plata  Mountains,"  Tmnn.  Amer.  Inst.  Min.  Eiuj..  XIII, 
'IHI.  G.  K.  Gilbert,  "Colorado  Plateau  Province  as  a  Field  for  (ieolojfical 
Study,"  ^-1/H<'r.  Joxv.  Sci.,  iii.,  XII.,  Hi,  S.").  J.  D.  llas;ue.  Fortieth  Poral- 
M  Siirreif,  \o\.  III.,  [).  475.  F.  V.  Hayden,  Pepx.  of  ITfti/deii's  Surrey, 
1H7.3,  1874,  p.  40:  1X75,  ]).  :!:];  187(i,  pp.  5,  70.  R.  C.  Hills,  "Preliminary 
Notes  on  the  Eru])t ions  ol"  the  Spanish  Peaks,"  Proc  Colo.  Sci.  Soc.  III., 
24,  224.  "The  Recently  Discovered  Tertiary  Beds  of  the  Huerfano  River 
Hasin,  '  Proc  Colo.  Sci.  Soc,  III.,  pp.  148,  217.  "  Jura  Trias  of  South- 
eastern Colorado,"  Amer.  Join:  Sci.  m..  XXIII.,]),  24;l  "Orographic 
and  Structural  Features  of  Rocky  Mountain  Geology,"  Proc.  Colo.  Sci 


288 


KEMP'S  ORE  DEPOSITS. 


M 


and  no  selvage.  {'I)  Large,  strong,  gold-bearing  veins  dipping 
(!0°  with  selvages  and  intersecting  (1).  (.J)  Like  (1),  but  larger 
and  more  persistent,  and  carrying  occasional  bismuth  and  anti- 
monial  ores  with  gold  and  little  or  no  silver.  T.  B.  Conistock 
{Trc-tiis.  Amer.  Inst.  Min.  Eng.,  XV.,  21.S)  has  classified  the 
veins  in  three  radiating  systems.  (1)  The  northwest,  with 
tetrahedrite  (freibergite).  {'i)  The  east  and  west,  with  bismuth 
and  less  often  nickel  and  molybdenum.  (;j)  Tlie  northeast, 
with  tellurides  and  antimony  and  sulphur  conipounds  of  the 
precious  metals.  Quite  recently  a  series  of  small  caves  near 
Ouray,  in  quartzite  overlaid  by  bituminous  shales  have  been 
found  to  contain  native  gold,  and  have  excited  great  interest. 
It  is  thought  by  Endlich  that  they  re})resent  iuclusitjns  of 
shale,  now  dissolved  away,  and  that  the  gold  was  precipitated 
on  the  walls.  If  this  view  is  correct,  they  mark  one  of  the 
very  few  illustrations  of  chamber  deposits  which  are  known. 
More  extended  mining  work  has  proved  them  to  be  in  all  oases 
connected  with  a  supply  fissure  from  which  small  leaders  guide 
the  miners  to  the  chambers. 

In  the  vicinity  of  Telluride  there  is  a  very  interesting  devel- 
opment of  veins.     One  of  the  most  remarkable  and  jiersisteut 

Soc. ,  III. ,  303.  Kee.  ' '  Tyi)es  of  Past  Eruptions  in  the  Rocky  Mountains," 
Idcm,IV.,  14.  Kt'c.  A.Lukes,  "  Extinct  Volcanoes  in  Colorado," -c4;(((r. 
Geol.,  January,  1890,  p.  38.  Oscar  Loew,  "Keport  on  the  Minerals  of 
Colorado  and  New  Mexico,"  Wticclcr's  Siinry,  1S75,  p.  U7.  "Erui)tivo 
Rocks  of  Colorado,"  Wheeler's  Survey,  1873.  C.  A.  II.  McCauley,  "On 
the  San  Juan  Region,"  lie}).  Chief  of  U.  S.  Engineers,  1878,  III.,  p.  175;). 
C.  S.  Palmer,  "On  the  Eruptive  Rocks  of  Boulder  County,"  etc.,  Pvoc. 
Colo.  Sci.  Soc.  III.,  p.  230.  A.  C.  Peale,  "On  the  Age  of  the  Rocky 
Mountains  in  Colorado,"  Amer.  Jour.  Sei.,  in.,  XIII.,  p.  172;  Rejjly  to  tlie 
above  hy  J.  J.  Stevenson,  Atiur.  Jour.  Sei.,  iii.,  XIII.,  2fl7.  T.  A.  Eick- 
ard,  "Cold  Resources  of  Colorado,"  The  Mineral  Industry,  II.,  32r);  IV., 
31.1  S.  H.  Scudder,  "The  Tertiary  Lake  Basin  at  Floris.sant," //a(/t/(';('.s 
Survey,  1878,  p.  271;  see  also  1877.  J.  A.  Smith,  Catalogue  of  tlie  Prinei- 
pal  Miuerids  of  Colorado,  Central  City,  1870.  J.  J.  Stevenson,  "  Notes  on 
the  Laramie  Group  of  Southern  Colorado,"  .cl»<cr.  Jour.  Sci.,  iii.,  XVIIl., 
129.  "TheMesozoio  Rocks  of  Southern  Colorado,"  ^mer.  Geol.,  III.,  p. 
391.  P.  H.  Van  Di est,  "  Colorado  Volcanic  Cones,"  Proc.  Colo.  Sci.  Soc, 
III.,  p.  19.  C.  A.  White,  "On  Northwestern  Colorado,"  2<^iidh  Ann.  Pep- 
Director  U.  S.  Geol.  Survey,  683-710.  For  the  complete  geological  bihii 
ograi)hy  of  the  State,  see  Bulletins  U.  S.  Geol.  Survey.  127  (1732-1891) ;  t:iO 
(1892-93);  135  (1894);  14G  (1895);  149  (1890);  150  (1897),  and  current 
annuals. 


IT 


SILVER  AND   GOLD. 


289 


is  the   Smuggler,  recently   described    by  J.  A.  Porter.     It    is 
Known  for  a  stretch  of  four  miles  and  cuts  tbe  bigh  divide  tbat 


Not  Classllled 

1 

as  to           < 

Gt'okifie  Age. 

2 

UhyoHtos  and 

Aiidesites. 

San  Juan  Formation 
AnJe»itic  Breccia 


Eocene? 

JuroKslc  and 
Cretaceous 


Suu  Mi^'uel 
Cuut^IoiuL-ruta 

Rliaies  and 
tiandstunei. 


Fl(i.  1()'2. — Gcolofiical  Hkctch-mnp  of  the  Tvllurulf  distrirt.  ColorniJ'K     Ajtcr 
Arthur  Wiiislow,  Trans.  Annr.  Inst.  Miii.  Kng.,  Frhrntiri/,  1W09. 

separates  the  Marshall  hasin  near  tbe  town  of  Telluride,  on 
the  south,  .in  the  drainage   area  of  tbe  San  Miguel  River,  from 


290 


KEMP'8  ORE  VEPOSITH. 


the  valleys  of  Canon  Creek,  a  tributary  of  the  Uncompahgn* 
River,  that  lies  to  the  north.  (See  Fig.  10'^.)  The  sunmiit  of 
the  divide  is  i;{,;i()()  feet  above  tide.  Whitman  Cross  has  bwn 
mapping  an  atlas  sheet  for  the  U.  S.  Geological  Survey  in  the 
vicinity  of  Telluride,  and  has  prepared  in  advance  of  its  issue 
a  sketch  of  the  local  geology.  ("The  San  Miguel  Formation. 
Igneous  Rocks  of  the  Telluride  District,"  Pt'oc.  Colo.  Set.  Soc, 
September,  IHDO.)  The  formations  of  interest  in  connection  with 
the  vein,  begin  with  the  San  Miguel  conglomerate,  which  is 
probably  of  closing  Cretaceous  or  early  Eocene  age.  On  this 
is  the  San  Juan  formation,  2,000  feet  thick,  of  bedded  volcanic 
andesitio  tuffs,  the  chief  wall  rocks.  Above  follow  sheets  of 
various  andesites  and  rhyoliti.-s,  which  are  cut  by  the  highest 
parts  of  the  vein.  The  fissiure  containing  the  ore  body  has  cut 
this  series  and  is  known  for  3J>{)(}  feet  vertically,  but  what  its 
character  is  in  the  San  Miguel  conglomerate  is  not  yet  demon- 
strated. The  gangue  is  chiefly  quartz,  with  some  rhodochrosito, 
calcite,  siderite  and  barite.  The  values  in  silver  are  highest  at 
the  north,  and  yield  to  gold  values  to  the  south.  Two  other 
notable  veins  cross  and  fault  the  Smuggler,  one  the  Pandora, 
containing  auriferous  (partz,  the  other  the  Revenue,  with  con- 
siderable lead.  So  constant  is  the  character  of  the  Smuggler 
thatstoping  ground  has  been  broken  for  a  mile  without  a  break. 
(J.  A.  Porter,  "The  Smuggler-Union  Mines,  Telluride,  Colo.," 
Trans.  Aincr.  Inst.  Min.  En<j.,  XXVI.,  449.)  The  region  is 
indeed  one  of  remarkably  persistent  and  clear-cut  fissures,' 
which  are  shown  on  Fig.  lO'^. 

Placer  gold  mines  (Example  44)  are  quite  extensively 
worked  in  San  Miguel  County.  J.  B.  Farish  has  de- 
scribed the  veins  at  Newman  Hill,  near  Rico,  in  a  valuable 
paper  cited  below.  The  lowest  formation  exposed  ia  magnesian 
limestone,  supposed  to  'be  Carboniferous.  It  contains  large  ore 
bodies  of  low  grade,  and  is  also,  strangely  enough,  heavily 
charged  with  carbonic  acid  gas.  Above  this  for  500  feet  are 
alternating  sandstones  and  shales,  and  then  a  narrow  stratum 
of  limestone  18  to  30  inches  thick.     This  is  followed  by  about 


'  C.  W.  Purington,  "  Preliminary  Report  on  the  Mining  Industries  of 
the  Telluride  Qu;idrangle,"  Eidhtcoith  Ann.  licp.  Director  U.  S.  (>'<"/. 
Survey.  Arthur  Winslow,  "The  Liberty  Bell  (iold  Mine,  Telluride.  Colo- 
rado," Trans.  Anicr.  In.'it.  Min.  Eng.,  February,  IMCQ. 


BlLVKIi  AM)   (}(fLJ). 


391 


?i 


A 


:? 


eq 


Ci5 


0( 


l»2 


KHMn'S  (HIE  DFA'OSlTti. 


500  feet  additional  of  slialea  and  sandHtone,  regarded  as  Car- 
bouiforouH.  Fifty  feet  above  tbe  lowest  liniestone  a  laccolite 
of  porpbyrite  bas  been  intruded.  Two  sets  of  fisHiires  are  \^xm- 
eut— one  nearly  vertical  and  striking  nortbeast,  tbe  second  dip- 
ping ;U)  to  45°  nortbeast,  and  striking  nortbwest.  Tbe  fornu'r 
are  tbe  ricb»)st,  are  rudely  banded  and  persistent,  being  worked 
in  one  case  for  1, (»()()  feet.  Tbe  flatter  fissures  are  le^s  rich. 
Tbe  principal  ore  bodies,  bovvever,  occur  as  borizontal  enlarge- 
ments ot  botb  tbese  sets  of  veins.  Just  over  tbe  tbin  bed  of 
liinestoM*^  mentioned  above  tbe  ores  bave  s])rea(l  out  iut<j  wbeets 
from  %)  to  40  feet  wide,  and  from  a  few  incbes  to  tbree  feet 
tbick.  Tbey  consist  of  solid  masses  of  tbe  common  sidpbidos, 
galena,  pyrite,  gray  cojjper,  etc.,  and  are   very    ricb.     Above 


ry^.j 


r,^.^ 


■~~J  J  ^  c^  ■ 


Fio.  104. — Geological  croHs  scctiDiiH  of  xtvata  n)i(l  vniiH  at  Ni'W)nan  Hill,  near 

Rico,  Colo.     After  J.  li.  Forixh,  I'roc.  Colo.  Sci.  iSoc, 

April  4,  1803.     See  also  Figures  5  and  6. 

them  the  fissures  apparently  cease,  or  at  least  are  tight.  Two 
hundred  feet  down  from  them  the  vein  filling  becomes  nearly 
barren,  glassy  quartz.  Tbese  are  most  remarkable  ore  bodies, 
and  would  appear  to  have  been  formed  by  uprising  solutions. 
which  met  the  tight  place  and  spread  sidewise,  depositing  their 
minerals;  but  as  jVlr.  Fari.sb  advances  no  explanation,  it  is 
hardly  justifiable  for  others,  less  famil'  '  '  "  inself  witli 
tbe  phenomena,  to  do  so.  T.  A.  Hie' 
them,  and  has  illustrated  tbe  d 
significant  series  of  plates,  win.  -.liow 
regular  and  not  persistent.  He  has  al 
rected  interpretations  of  the  faults. 

Tbe  lead-silver  ores  of   Red  Mountain   and    Rico  ha^     al- 


()  written  of 
.«su        ire  in  a  very 
bai   .ing   to   be  ir- 
mtroduced  some  cor 


SILVER  AND  GOLD. 


293 


n^ady  been  mentioned  ('^.OK.  17).     Silverton  and  Ouray  are  tiio 
principal  townn  of  the  San  tluan.' 

y.OlMl.  The  new  mining  region  of  Creede,  now  decided  to 
be  in  Saguache  County,  whonld  be  menti<jued  in  thin  connec- 
tion. It  is  situated  near  the  junction  of  Saguache,  Ouray  and 
Hinadalo  counties,  and  some  ifii  or  twelve  miles  from  Wagon 
\Vl]eel  Gap.  There  is  a  great  devolopnicnt  of  igneous  rocks 
as  well  as  of  Carboniferous  limestone,  but  the  veins  as  j'wt  devel- 
oped are  in  the  former.  They  appear  to  he  fissure  veins,  and 
have  quartz,  in  largo  part  amethyst,  with  some  manganese 
minerals  as  a  gangue,  and,  with  these,  oxidized  silver  ores.  The 
niiueM  are  on  two  mountains,  I^achelor  and  Campbell,  wliich 
are  on  opposite  sides  of  Willow  Creek  Canon. ^ 


'  T.  li.  Comstoclv,    'The  (^tcolo^y  ami  Vein  Structiu-e  of  Soutliwestern 
Cildi-iiilo."  TmH.s.  Amvi:  Insf.  Min.  A;*/;/.,  Vol.  XV., ')IS:  niso  XI.,  Km.  jvnd 
Fjiil.  and  Mill.  Join:,  numcrdus  1)!1|h'Is  in  ISS.").     ■•  Hot  Si)iin;:;  I'orniation 
in  the  Red  Moiuitmn  District,  ("olorado,"  Tniiin.  Aiini:  Just.  Min.  Kiii/., 
.WII..    2lU.    S.    F.    Enunons,    "On    tho   San    Jnan    Disliict,"    /•-'/(;/.  and 
.Mill.  ./((»/•.,  June  Jt,  1HM:{,  p.  ;5:W.     "Structural  J{olation.s  of  On;  I )('|)o.sits," 
Trans.  Amrr.  hint.  Min.  En(f.,XVl..  H()4.     Reo.     Ti-ntli  Cciishs,  Vol.  XIll., 
]).  (111.     F.  ]Vr.  Kndlich.    '  Oiij^inof  tlu' (iold  Deiiosits  nearOiu-ay,"  A^/f/.  mid 
Mill.  Join..  October  1!»,  is.-iit.      "Sau.Iuan  District,"  Ilai/drn's Siirrri/.  jSM, 
]..  2-i\).     Ihiil,  is;.-).  Hull.  Ill,  Aiiin-.  Jonr.  ,Sc/..iii.,  X.,  oS.     .1.  D.  Faiisli, 
•On  the  Ore  Deposits  of  Newman  Hill,  near  Rico,  Colo.,"  Colo.  Sci.  Soc. 
.\l>ril4,  lS!t>.    Uec.     W.  Tl.  llolnics.  ••  La  Plata  District,"  IIaiid''ii\s Snrn'i/. 
ixr.");  Ainci:  Jonr.   Sci.,   iii.,   XIV.,  420.     M.  ('.  Ihlsenj^,  "  K'cview    of  tiio 
Mininj;  Interests  of  the  San   Juan   Refjion."  licp.  Colo.  Slalr  School  of 
Miiu'.^.    IHS,-.,  p.  27.     (!.  F,.   Kedzie,    "The   Bedded   Ore   Deposits   of  Red 
.Mniiutaiu  l\Iinin>i;  District,  Ouray  County,  Colorado,"  Tranx.  Aiiivr.  liixl. 
Mill.  Eng.,  XV.,  .-)70.    Reo.    (t.  A.  Koenis  and  M.  Stocker,  "  Lustrous  Coal 
.111(1  Native  Silver  in  a  Vein  in  Por])liyrv,  Oniay  County.  Colorado,"    Trims. 
Aiiirr.  Inst.  Min.  En(j.,  IX  ,  CmO.     T.  A.  lvMcl<ard,  "Vein  Structure  in  the 
F.nterpri.se  Mine,"  Proc.    Colo.    Sci.    Soc.    Adv.    Sheets,    Vol,   \'.     T.   K. 
Schwartz,  "The  Ore  Deposits  of  Red  ^Founta in,  Ouray  County,  Colorado," 
Tnni.-i.  Aiiicr.  Insf.  Miii.  Enij..    XVIIL,  i:i'.),  ISSll.     J.   J.  Stevenson,  "On 
tlie  Stui  Juan,"  Wlicrh'r'x  Snrrrii.   TIT.,  ]).  ;!Tt'>.      "The  San  Juan  l»e}j;ioTi,  ' 
/wif/.  and  Min.  Jonr..  Au,t?u,st  27,  IS.Mj,  j).  l:',(i:  Septendier  2 1,  IS8|,  p.  201 ; 
July  ir,  Is^SO;  Decendter  20.  1^70;  and  many  otluM'  refenMu-es  in  1870  and 
l^^^O.     r.  TI.  Van  Die.st.  "Notes  on  a  Trip  to  Telluride,  San  :\liKU«'l  Co.. 
''f.lo  ,"  Proc.  Colo.  Sci.  Soc,  XL.  28,  1885;  Idem,  January.  188(5. 

''  K.  R.  Kirby,    "The  Ore   Deposits  of  Creede  and  their  l\)ssibilities," 
Eng.  and.  Min.  Jonr.,  March  10,  1S02,   p.  :?2r).     Rec.     T.  R.  MacMechen, 
"'Ihe  Ore  Deposits  of  Creede,"  Eng.  and  Min.  Jour.,  March  12,  1802,  p 
301.     Rec. 


-■■i,, 


ii 


ill 


394 


KEMPS  ORE  DEPOSITS. 


2.09.12.  The  Gunnison  region  lies  on  the  western  slope  of  the 
Continental  Divide,  and  embraces  both  mountains  aud  pla- 
teaus. West  of  the  main  and  older  range  are  the  later  Elk 
Mountains,  in  which  several  miniiig  districts  are  located. 
Aspen  has  already  been  mentioned,  and  the  long  series  of  ore 
bodies  in  the  Carboniferous  limestones.  The  other  principal 
districts  are  Independence,  Ruby,  Gothic,  Pitkin  and  Tin 
Cup.  The  ores  at  Independence  are  sulphides  with  silver,  in 
the  Archean  granite  rocks.  In  the  Tin  Cup  district  the  Gold 
Cup  mine  is  in  a  black  limestone  and  contains  argentiferous 
cerussite  and  copper  oxide.  In  the  Ruby  district  the  ores  are 
in  the  Cretaceous  rocks,  aud  in  the  Forest  Queen  they  are  rnby 
silver  and  arsenopyrite,  partly  replacing  a  porphyry  dike.  On 
Copper  Creek,  near  Gothic,  a  series  of  nearly  vertical  fissures 
traverse  eruptive  diorite.  They  contain  sulphide  of  silver  and 
native  silver.  The  Sylvanite  is  one  of  the  principal  mines. 
Arthur  Lakes  has  described  some  very  curious  veins  in 
Gunnison  Co.,  the  Vulcan  and  Mammoth,  that  contain  opaline 
silica  and  native  sulphur  together  with  pyrites.' 

2.01).  1.'}.  Eagle  County.  The  lead-silver  mines  of  Red  Cliff 
have  already  been  mentioned  (Example  ;>0(),  and  also  the 
underlying  gold  deposits.  The  Honiestuke  mine,  northwest  of 
Leadville,  over  toward  Red  Cliff,  is  on  a  vein  of  galena  in 
granite,  and  was  one  of  the  first  opeiiings  made  in  the  region." 

&.0I).14.  Summit  County.  The  Ten-Mile  district,  which  is 
the  principal  one,  has  been  mentioned  under  P]xample  30«. 
Lake  Count}',  containing  Leadville,  has  been  treated  under 
Example  ;)0.     Mention  should  also  be  made  of  the  placer  depos- 

'  F.  Amelung,  "Slieep  JEoiiutain  ]\iines,  Cunnison  County,  Colo.,"  Evg. 
andMin.  Jour.,  August  28,  1SH»;,  p.  14i».  F.  M.  Cliadwick,  "Tlie  Tin  (  ii]) 
Mines,  Gunnison  C^oanty,  Colorado."  Eiig.  and  Min.  Jour.,  .Jainiaiy  1, 
1881,  p.  1.  See  also  E.\anii)le  \'id  for  iron  mines.  J.  K.  Iloliliau^li, 
"Gold  Belt  of  Pitkin,  Gunnison  Co.,  Colo.,"£;(!7.  and  Min.  Jour.,  Decem- 
ber 13,  ISlKi.  p.  r).">!>.  Artlinr  Lakes.  "  Sketeh  of  a  Fortion  of  the  Gunni- 
son Gold  Belt,"  etc.,  TvKHS.  Amcr.  Just.  Min.  Enij.,  XXVI..  440. 

"  F.  (Juiternian,  "On  the  (^.old  Deno.sits  of  Eed  Clitf,  '  Proc.  Colo.  Sci. 
Sac.  181)0.  "On  the  Battle  ^Mountain  (^nart/.ite  iMines."  Minimj Indiiainj. 
Denver.  January  10,  IHilO,  p.  iS.  E.  E.  Oleott,  "Battle  Mountain  Jliuinj,' 
District,  Eagle  County,"  F.ng.  and  Min.  Jour.,  June  11  and  18,  188T,  jiji 
417,  430;  IMay  21,  lHi)3.  G.  C.  Tilden,  "Mi.iing  Notes  from  Eagle  County, " 
Ann.  Rep.  Colo.  State  Seliool  of  Mine.'i,  188(5,  p.  121). 


i 


MP! 


Si 


SILVER  AND  GOLD. 


^95 


its  in  California  Gulch,  which  first  attracted  prospectors  to  the 
region  in  ISCO.  In  its  eastern  part  Summit  County  borders  on 
Clear  Creek  County,  and  at  Argentine  are  some  veins  related 
to  those  of  the  latter.  They  are  high  up  on  Mount  McClellan, 
and  are  remarkable  for  the  veins  of  ice  that  are  found  in  them/ 

a, 09. 15.  Park  County,  which  lies  east  of  Lake  County  and 
embraces  the  South  Park,  has  some  mines  on  the  eastern  slope 
of  the  Mostjuito  range,  and  in  the  Colorado  range,  to  the  north- 
west. The  latter  are  similar  in  their  contents  to  ti^e  George- 
town silver  ores,  mentioned  under  Clear  Creek  County,  but  the 
former  are  bodies  of  argentiferous  galena  and  its  alteration 
products  in  limestone  and  (juartzite.  Pyrite  is  also  abundant, 
and  at  times  a  gangue  of  barite  appears.  The  mines  are  in  the 
sedimentary  series,  resting  on  the  granite  of  the  Mostpiito 
range,  and  are  pierced  b}'  porphyry  intrusions,  as  at  Leadville. 
The  placer  ileposita  at  Fair  play  deserve  mention,  as  it  wrs 
from  these  that  the  prospectors  spread  over  the  divide  to  the  site 
of  Leadville  in  ISGO.^ 

2.09.10.  Chaffee  Count}',  on  the  south,  contains  the  iron 
mines  referred  to  under  Example  \'id.  There  are  some  other 
gold-bearing  veins  near  Granite  and  Buena  Vista.  The  lead- 
silver  deposits  of  the  Monarch  district  are  mentioned  under 
Example  '{o/>.  In  Huerfano  County,  in  the  Spanish  Peaks, 
veins  of  galena,  gray  copper,  etc.,  are  worked  to  some  ex- 
tent.^* 

2.09.17.  Rio  Grande  County.  In  tlie  Summit  district  are 
a  number  of  rich  gold  mines,  of  which  the  Little  Annie  is  the 
best  known.  The  gold  occurs  in  the  native  state,  in  quartz 
on  the  contact  between  a  rhyolite  and  trachyte  breccia  and 
andesite.  The  de|K)sitsare  thought  by  R.  C.  Hills  to  be  due  to 
a  i^ilicificationof  the  rhyolite  along  those  lines,  probably  by  the 
sulplnu'ic  acid,  which  brought  the  gold.  Then  the  rocks  were 
fdldod.     Oxidation  and  impoverishment  of  the  upper  parts  fol- 


'  H.  L.  northoud,  "On  Rifts  of  loe  in  the  Rocks  near  the  Summit  of 
i^fouiit  Mf^CleUan,"  etc.,  Amer.  Jour.  ScL,  iii.,  II.,  108.  Ten  Mile  Special 
Folio,  U.  S.  Gi'ol.  Snrrcti,  by  S.  F.  Emmons.     Rec. 

'^  J.  L.  Jernegan,  "Whale  Lode  of  Park  Count},"  Trans.  Amer.  Inst. 
Min.  Emi.  III.,  m-1. 

'  R.  C.  Hills,  "  On  the  Eruption  of  the  Spanish  Peaks,"  Proc.  Colo.  Sci. 
Soc,  III  .  pp,  24,  224. 


296 


KEMP'S  ORE  JJKPOSIT.^. 


lowed,  forming  bonanzas  below.     The  paper  has  a  very  impor- 
tant bearing  on  the  formation  of  man}'  replacements/ 

2.01).  18.  Conejos  County.  Some  deposits  of  ruby  silver 
ores  have  recently  been  developed  in  this  county,  near  the 
town  of  Platoro.  The  county  lies  near  the  middle  of  the  south- 
ern tier. 

2.0'.i.l9.  Custer  County  affords  some  of  the  most  interesting 
deposits  iu  the  West.  Rosita  and  Silver  Cliff  are  the  principal 
towns,  and  are  situated  in  the  Wet  Mountain  Valley,  between 
the  Colorado  range  on  the  north  and  the  Sangre  de  Cristo  on 
the  south.  In  the  northern  poi'tion  of  the  area  immediately 
concerned  with  the  mines  gneisses  of  undeterniiued  but  proba- 
bly very  ancient  age  outcrop,  which,  to  the  south,  are  buried 
beneath  an  extensive  development  of  igneous  (mostly  volcanic) 
rocks,  and  Pleistocene  gravels,  alluvium  and  lake  beds.  The 
ign*'ous  rocks  embrace  rbyolite,  trachyte,  dacite,  three  varie- 
ties of  andesite,  diorite,  agglomerate  and  tuffs.  The  volcanic 
rocks  were  derived  from  outbreaks  that  took  place  during  the 
Eocene,  as  nearly  as  can  be  determined  by  some  fossil  leaves 
which  are  buried  in  the  tuft's.  It  is  interesting  to  note  that  the 
Cripple  Creek  volcanic  center  lies  about  40  miles  north.  The 
volcanic  rocks  are  chiefly  represented  in  the  Rosita  Hills  near 
the  town  of  the  same  name,  and  in  the  flow  of  rbyolite  north 
of  Silver  Cliff.  In  addition  to  the  volcanics  there  are  syenite, 
granite  and  diabase  in  the  gneisses.  Several  different  forms 
of  ore  body  have  been  developed,  each  of  which  possesses  exceji- 
tional  claims  to  interest,  and  one  of  which  forms  a  (]uite  unique 
type,  at  least,  so  far  as  American  experience  has  yet  gone. 

2.09.20.  Example  ;5'.).  The  Bassick  Mine.  An  explosive 
volcano  seems  to  have  broken  out  at  the  situation  of  the  Bas- 
sick mine,  and  to  have  produced  an  elliptical  pipe  or  conduit 
about  l,r)O0x  1,000  feet  in  the  fundamental  gneiss  of  the  dis- 
trict, and  to  have  subsided,  leavii-g  the  tube  iilled  with 
rounded  boulders,  which  are  chiefly  andesite,  but  which  em- 
brace also  granite,  gneiss  a^^d  even  carbonized  wood.  A  sniidl 
dike  of  basaltic  rock  (limburgite)  is  also  known  to  be  present. 
A  portion  of  the  agglomerate  in  the  shape  of  one  and  perha])s 
more,  nearly  vertical  pipes  or  chimneys,  has  been  impregnated 

'  K.  V.  Hills,  Proc.   Colo.  Sci.   Soc,    March,    ISHIJ.     Alistract    by   S    F. 
Emmons  in  the  £/((/.  and  Miu.  Junr.,  June  1),  ISH:},  p.  ;iS2. 


i 


>SILVER  AND  GOLD. 


it^it 


with  rich  ores  of  gold  and  silver,  which  coat  the  rounded  boul- 
ders in  successive  shells  of  metallic  minerals.  The  first  coat  is 
a  mixture  of  lead,  antimony  and  zinc  sulphides,  and  is  always 
present.  A  second,  somewhat  similar,  but  of  lighter  color  and 
richer  in  lead  and  the  precious  metals,  is  sometimes  seen,  A 
third  is  chiefly  zincblende,  rich  in  silver  and  gold,  and  is  the 
largest  of  all.  A  fourth,  of  chalcopyrite,  sometimes  occurs, 
fuul  lastly,  a  fifth,  of  pyrite.  Some  lots  of  ore  also  yielded  rich 
tellurides  of  the  precious  metals.  On  the  Bassick  chimney  the 
workings  have  gone  to  1, 4(H)  feet  in  depth,  without  losing  the 
ore,  which  was  roughly  elliptical  and  l(iOxt>()  to  ;{()  feet.  From 
the  seventh  level  downward  cross-cuts  opened  up  a  second 
chimney  lying  150  feet  east.  The  Bassick  has  been  considered 
by  the  earlier  observers  to  be  a  geyser  tube  in  which  the  bowl- 
ders were  tossed  about,  rounded  and  coated  with  ore.  Whit- 
niau  Cross  has,  however,  satisfactorily  demonstrated  the  exist- 
ence of  the  agglomerate,  and  S.  F.  Emmuns  has  reached  the 
c'Diiclusion  that  the  ores  have  come  in  through  fissures  which 
can  be  detected  in  the  mine.  At  the  intersection  of  two  which 
cross  each  other,  the  chief  ore  body  has  been  found.  The  ores 
are  of  such  a  nature  that  Emmons  regards  their  introduction 
in  the  form  of  vapors  as  possible,  although  at  depths  these 
va{)ors  were  probably  confined  in  the  litjuid  state.  The  ores 
would  then  befumarolic  imi)regnations  which  have  replaced  the 
interstitial  filling  of  the  agglomerate. 

Example  39a.  The  Bull  Domingo  Mine.  The  Bull  Do- 
mingo lies  north  of  Silver  Cliff  and  some  miles  northwest  from 
tliB  Bassick.  The  country'  rock  is  the  ancient  gneiss,  but  near 
tlio  mine  dikes  of  granite  and  syenite  are  known.  The  ore  was 
found  in  an  elliptical  chimney,  of  variable  size,  but  at  the  l.'x) 
foot  level.  !iOx4()  feet.  It  has  bean  exploited  down  to  the  ht){) 
level.  The  ore  consists  of  rounded  boulders  of  gneiss,  syenite 
and  granite,  which  are  coated  with  successive  shells  of  coarsely 
crystalline  galena,  somewhat  fibrous  zincblende.  and  specks  of 
pyrite.  Outside  these  are  in  order  shells  of  white  dolomite, 
ankerite  or  siderite,  calcite,  and  chalcedony.  There  is  abun- 
dant evidence  of  extensive  fracturing  of  the  rocks  at  the  mine, 
and  the  evidence  points,  according  to  S.  F.  Emmons,  rather  to 
a  shattered  mass  of  country  rock,  whose  brecciated  fragments 
have   been  rounded,  replaced  and  coated  with  ore  by  uprising 


298 


KEMP'S  ORE  DEPOSITS. 


solutions,  than  to  an  explosive  volcanic  outbreak  or  geyser,  as 
had  been  previously  thougbt.  The  general  similarity  in  struct- 
ure of  the  ore  to  that  of  the  Bassick  suggested  quite  naturally 
a  similar  origin  to  the  earlier  observers.     It  is  interesting  to 


tllllllLl 


m 


m 

■  vM-  ■-•'-— 


m 


mmm 


m 


':■•:>: 

"■,".•0- 

m 


,■?■■»> 

:■'%.> 

IP 
r.a.  - 


o'-p 

•K;10 


fSli 


i:i 


».'::i&': 


E. 


''-■W^ 


i>";|!5^'5i 


^# 


W  Jo* 


Fig.  105. 


Hew  Shaft      nil'^Iuft 


Fig.  106. 


Fig.  105. — ('rons  mction  of  the  Bnsaic  Mine,  near  Rosita.  After  S.  F.  Emmons, 

XVII.  Ann.  Rep.  LL  S.  Oeol.  Survey,  Part  II,  p.  434. 

Fig.  10(!. — CfoMd  section  (fthe  /hillPominffo  Mine,  near  Silver  (2iff,  Colo. 

After  S.  F.  Kmmons,  X  \  II.  Ann.  Rep.  U.  S.  (leol.  Survey, 

Part  11,2).  443. 


compare  the  two  chimney's  of  the  Rasaick  and  Bull  Domingo 
with  tbat  of  the  Annie  Lee  at  Victor  in  the  Cripple  Croek 
district.     Specimens  and  notes  given  the  writer  by  E.  J.  Chibas 


•nni'T-iiiriMiroP  n- 1  r-  [f-niiiMmMMi 


SILVER  AND   GOLD. 


299 


would  indicate  a  similar  deposit  at  the  mines  of  the  Darien 
Gold  Mining  Company,  Cana,  Columbia.  (See  also  E.  R. 
Woakes,  AiL3r.  Inst.  Min.  Eng.,  Atlantic  City  meeting,  Feb- 
ruary, 1808.) 

a.0t),'21.  Humboldt-Pocahontas.  This  vein  is  one  of  sev- 
eral which  have  been  discovered  near  Rosita.  It  is  a  fissure 
vem  which  cut  in  its  upper  portion  a  mass  of  andesite  and 
andesite  breccia,  but  which  at  the  fourth  level,  as  shown  in 
Fig.  107,  forked  into  several  feeders.  Above  this  point  it  was 
one  of  the  most  regular  and  clear-cut  fissures  ever  mined  in 
the  West.     The  ore  was  tetrahedrite  in  a  gangue  of  barite  and 


ROSITA 
ANDESITE 


TRACHYTE 
POKPIIYRY 


GRANITE 


BROKEN  ZONE 

OF  IH)UPIIYRT 

&  ANDESITE 

Fm.  107. — f'rofisseetionofthe  [fuinlxiMf-Pocdliontait  vein,  near  Rosita,  Colo. 

After  S.  F.  Emmons,  XVfl.  Ann.  Hep.  U.  S.  Ueol.  Survey, 

Pnvt  11.,  p.  427 


•Ipoomposed  wall  rock,  with  which  were  associated  chalcopy- 
rite,  pyrite,  galena  and  antimonial  sulphides  of  silver.  In  the 
lower  levels  the  vein  bi-oke  up  into  several  small  fissures  and 
troubles,  such  that  operations  ceased. 

2.00.23.  Silver  Cliff.  At  Silver  Cliff  there  is  a  large  flow 
of  })or()U8  rhyolite  just  north  of  the  town,  which  was  early 
fouufl  to  be  impregnufed  along  small  fissures,  with  chloride  of 
silver  and  black  manganese  minerals.  For  a  time  free-mill- 
ing ore  was  (piarried.  Later  a  deep  shaft  was  sunk  in  tli(!  Gey- 
ser mine,  which  at  1.850  feet  found  the  faulted  contact  with  the 


300 


KEMP'S  ORE  DEPOSITS. 


m 
ill 


Arcbean  gneiss  and  ^00  out  into  the  rliyolitic  tuff  a  cross-cut 
encountered  a  vein  tbat  proved  j)roductive  of  rich  silver  ore. 
This  deep  shaft  atl'orded  some  interesting  samples  of  deep  and 
vadose  waters,  which  have  been  analj'zed  by  W.  H,  Hille- 
brand,  as  given  in  Emmons'  paper  (see  above  p,  ;51).  The 
rbyolite  also  afforded  in  the  surface  workings  some  extraordi- 
narily large  spherulites  which  have  been  described  by  Cross. 
Assays  of  fresh  and  unaltered  samples  of  the  country  rocks, 
which  were  made  fur  S.  F.  Emmons,  indicated  the  presence  of 
silver  in  five  out  of  nine,  viz. :  trachyte,  0.007  oz.  per  ton;  Fair- 
view  diorite,  0.01  oz.  per  ton;  rbyolite,  0.402  oz.  per  ton;  red 
granite,  0.005  oz.  per  ton;  black  granite,  O.O'-io  oz.  per  ton; 
bisilicates  of  the  granite,  0.04  oz.  silver  per  ton,  and  0.045  per 
cent,  lead.' 

2.01>.'M.  Teller  Coimty.  The  region  of  Cripple  Creek  is  the 
only  one  of  serious  impcrtance  in  this  county,  but  the  remarka- 
ble developments  of  the  last  few  years  have  placed  it  in  a  very 
imjHirtaut  position.  The  productive  mines  are  situated  in  the 
foothills  of  Pike's  Peak,  about  ten  miles  west  from  the  peak 
itself.  The  summit  is  clearly  visible  from  many  of  them,  as 
are  also  the  peaks  of  t'.ie  Saugre  de  Cristo  range,  many  miles  to 
the  south.  The  town  of  Cripple  Creek  lies  in  the  valley  of  the 
small  stream  of  the  same  name,  which  is  a  branch  of  Oil 
Creek,  itself  a  tributary  of  the  Arkansas  River.  The  valley  is 
an  open  and  moderately  broad  upland,  hut  the  approaching 
depressions  are  narrow  detiles,  that  have  presented  great  diffi- 
culties to  railways.  The  general  country  rock  of  the  re^i(jn  is 
the  red  granite  of  Pike  s  Peak.  This  contains  masses  of  still 
older  mica  schists,  presumably  caught  up  in  its  intrusion.   'I'lu' 


'  R.  N.  Clark,  "  ITuniboldt  rocalioiiliis  VtMii,"  Tntiin.  Aiiicr.  Inst.  Miii 
Eiig.,  VII.,  21.  "Silver  Cliff,  Colorado,'  Eikj.  diul  Min.  Jdhi'.,  Novciu 
ber  2,  1S78,  p.  JU4.  W.  Cross,  "Cieology  of  the  Rosita  Hills,"  Proc.  Cnln. 
Sci.  Soc,  18!)(),  |>.  2(U).  Rec.  Sevciitccuth  Ann.  licp.  U.  S.  Gcol.  Snrrrii. 
Part  II.,  209.  Rec.  S.  F.  Emiiious,  "  The  Genesis  of  Certain  Ore  Dt'pns 
its,"  Trans.  Avier.  Inst.  Min.  Entj.,  XV.,  146.  Tentli  Ci'nsus,  Vol.  XIII 
p.  80.  "The  Jlines  of  Custer  Countj%  Colo.,"  Seventeenth  Ann.  Pep  V. 
S.  Cenl.  Surveji.  Part  II.,  411.  Rec.  L.  C.  (Srnybill,  "On  the  Peculiar 
Features  of  the  Hassick  Mine,"  Trans.  Anier.  In.^t.  Min.  En<).,  XI.,  p.  11"; 
Enf/.  it  nil  Min.  Join:,  October  28,  1882,  p.  22(1.  Rec.  O.  Loew  and  A.  d. 
Coid<liiijjj.  "  K'osita  and  Vicinity,"  Wlieiler'^  Surrey,  18~(),  p.  48.  See  also 
Sttnenson  in  the  l\eiM)rt  for  1871'. 


ross-ciit 
ver  ore. 
eep  aiul 
.  Hille- 
l).    The 
ctraorcH- 
y  Cross. 
y  rocks, 
3seuce  of 
m;  Fair- 
ton;  red 
pin-  ton; 
).()45  per 

3ek  is  the 
reniarka- 
in  a  vt'vy 
ted  in  tlie 
the  peak 
:  them,  as 
|y  miles  to 
ley  ot'  tlie 
ch  of  Oil 
)  valley  is 
n-oachii'g 
reat  difH- 
re^ion  is 
,es  of  still 
siou.  The 

In^f.  Mill 
Inv,  Novcni 
I 'roc.  ('"<>'■ 
col.  Sin-rrji. 

Ore  l)t'l'"^ 
Vol.  XIII., 
nil.  Rep  U. 
Peculiar 
XT.,  p.  lilt; 
iv  uml  A.  li- 
Ib.     Set"  also 


302 


KEMP'S  ORE  DEPOSITS. 


schists  are  pre- Cambrian,  as  are  the  granites  and  certain  dia- 
hase  dikes  that  occur  in  the  streets  of  Cripple  Creek  and  on 
Mineral  Hill,  but  that  are  of  no  importance  in  connection  with 
the  ores.  At  the  close  of  tbe  Eocene  or  in  tlie  Miocene  times  a 
small  volcanic  center  broke  out  in  the  granite  hills  now  lying 
east  of  the  town,  and  perhaps  elsewhere.  It  was  marked  at 
first  by  explosive  activity  that  besprinkled  the  neighboring 
region  with  a  breccia  made  up  of  fragmejits  of  granite  and 
andesite.  Later  came  eruptions  of  pbonolite  of  one  or  two 
varieties  that  form  many  dikes  associated  with  the  ore  bodies. 
Some  minor  outcrops  of  nepheliue-syenite  and  syenite-porphyry 
are  possiblj'  deep-seated  and  coarsely  crystalline  representatives 
of  tbe  pbonolite  magma.  Explosive  eruptions  of  this  phase  seem 
also  to  have  contributed  some  pbonolite  to  later  breccias.  Last 
of  all,  dikes  of  several  kinds  of  basalt,  including  nepheline 
basalt,  feldspar  basalt,  and  limburgite,  closed  the  eruptive  phe- 
nomena. The  breccias,  after  their  formation,  became  in  many 
cases  silicitied,  so  as  to  produce  a  very  firm  rock,  and  as  a  rule 
are  so  altered  that  their  original  rock  is  to  be  recognized  more 
by  its  physical  texture  than  its  mineralogy.  In  areal  distribu- 
tion the  breccias  are  the  most  proujiu'ont  rocks  near  tbe  mines; 
next  follows  the  granite,  while  through  both  are  intruded  tbe 
dikes  of  pbonolite  and  basalt. 

The  ores  are  almost  entirely  productive  of  gold,  for  althongli 
some  little  silver  often  occurs  with  it,  and  although  lead,  zinc 
and  copper  minerals  are  met  in  one  or  two  mines,  the  former  is  of 
slight  economic  account  and  tbe  latter  are  rareties.  Iron  pyrites 
is  very  widespread,  but  it  is  not  a  great  carrier  of  gold.  The 
real  source  is  the  telluride  of  gold,  calaverite,  from  which 
more  or  less  of  the  native  metal  has  been  derived  in  the  uppor 
parts  of  tbe  veins  by  oxidation.  The  gangue  minerals  are 
quartz,  fluorite  and  decomposed  country  rock.  When  the  lat- 
ter is  granite,  it  has  lost  its  mica  and  often  its  quartz,  leaving 
a  cellular  rock  more  or  less  impregnated  with  fresh  or  decom- 
posed telluride.  The  wash  of  these  veins  has  yielded  some 
placer  diggings,  especially  on  Mineral  Hill. 

The  ore  deposits  are  true  veins  that  have  been  formed  alonf? 
lines  of  displacement  whose  amoimt  is,  as  a  rule,  slight.  The 
fissures  themselves  are  often  insignificant  in  appearance,  but 
the  impregnations  of  the  wall  rock  with  ore  to  a  width  of  from 


am  (lia- 

aiul  on 
on  with 

times  a 
iw  lying 
irked  at 
jhboriug 
uite  and 
)  or  two 
e  bodies, 
[lorpbyry 
entatives 
laseseein 
as.    Last 
aepbeliiie 
3tive  ])be- 
)  in  many 

as  a  rule 
ized  more 
I  distribu- 
be  mines; 

ruded  the 

although 
ead,  ziuc 

rmer  is  of 

on  pyrites 
1(1.     The 

n\\  which 
be  uppor 

lerals  are 
n  the  lat- 
z,  leaving 
or  deconi- 
led  some 


n 


ed  along 

bt.     The 

•ance,  hut 

h  of  from 


'««%^«rr^.' 


r.7Jk  ' 


Fig.  109. — Vietv  of  Cripple  Creeh  Colorado,  from  Mineral  Hill:  Gold  Hill 
in  the  bachjroiind.     From  a  photograph  by  J.  F.  Kemp,  ,'idi),  181)5. 


Flo.  110.  —  View  of  Battle  Mountain,  Victor,  Colorado.     Froina  window 

in  Victor.     The  Portland  group  of  mines  is  on  the  left  in  the 

bttehynntnd.     The  Independence  mine  /.s'  on  the 

e.ctreme  right.     From  a  photograjth  by 

J.  F.  Kemji.  July.  18!),-). 


i  sv-i'-'-'V;^''"''"''""''''*'''"     6 


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a 


1-1 

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o 


o 


O-., 


-1%' ': '■•ii'iAi^j 


304 


KKMrS  OJlh'  DFJ'OSITS. 


one  to  several  feot  afVord  very  rich  and  valuable  ore  bod- 
ies. Tiie  fisHurt'H  frocjueiitly  follt)W  tliocoursoHof  diki'H,  but  are 
(ilearly  later  tbau  tbe  latter  because  tliey  cross  tliein,  leave 
tliem,  return  to  t'lem,  and  behave  in  a  more  or  less  independent 
way.  Yet  the  presence  of  dikes  is  in  a  measure  a  favorable 
thinjjf,  because  the  dike  itself  has  filled  a  fissure,  and  because 
it,  bein^  an  offshoot  from  a  larj^er  body  of  heated  rock,  and 
with  lines  of  weakness  along  the  contacts  with  its  walls,  doubt- 
less baa  often  exercised  a  directing  influence  on  solutions.     The 


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[Flo.  112. — Stereoj/mm  of  the  Annie  Lee  ore-xfiort,  Victor,  Colo.    After  R.  x\. 
b'.  l'ii,ro,v;  XVI.  Ann.  Rep.  U.  .s'.  Oiol.  .^iirr,//,  Part  IT.,  p.  'M\. 

accompanying  map,  from  the  timely  and  valua))le  report  of 
Cross  and  Penrose,  which,  with  the  Pike's  Peak  Atlas  Sheet  of 
the  U.  S.  Geological  Survey,  should  be  consulted  by  all  wlio 
are  especially  interested  in  the  region,  will  give  the  main  fea- 
tures of  the  geology.  The  veins  are  not  large,  but  they  have 
yielded  in  the  aggregate  great  amounts  of  high  grade  ore.  As 
elsewhere  tbe  ores  follow  shoots  in  the  veins,  and  the  shoots 
approximate  the  vertical.  Small  cross  fractures  have  often 
exercised  an   influence  upon  them.     The  veins  themselves  are 


81L\l':ii   AM)   (!(HA). 


306 


also  often  in  a  serieH  of  Hinull  jiam He WiwHiires,  rather  than  in 
a  siiiK'»*  f'"*^  ""•'  iiii|)n'^iiato  tln«  inUuvtuiinj^  wailH.  Ore  has 
lji>t'ii  fuuiid  in  hlind  veinH,  outside  the  num.  lines  of  deposition, 
80  that  frecjuent  crosK-cuts  are  desirahle  to  make  sure  of  the 
country.  The  most  productive  section  is  on  l-5attle  Mountain, 
juHt  ahove  Victor.  The  Portland  j^ronp  and  the  famous  Inde- 
|)fU(lence,  of  which  a  cut  is  here  reproduced  from  Penrose's 
report,  are  in  this  hill.  Fi^.  1|-*  illustrates  the  Annie  Ijee 
ore- body,  a  very  curious  one  that  forms  a  chimney  in  a  basaltic 
dike.  Bull  Mountain,  with  its  spur.  Bull  CMitf,  contains  a 
considerable  number  around  the  town  of  Altman.  The  fissure 
on  which  the  Buena  Vista,  Lee  and  Victor  mines  are  located 
is  one  of  the  most  extended  in  the  district.  Raven  Hill,  (iold 
Hill,  (ilol)e  Hill  and  various  minor  spurs  have  also  yielded 
ini|iortant  bodies  of  ore.' 

It  has  been  customary  to  send  the  ores  up  to  S'^O  to  the  ton  to 
tlje  stamp  mills,  for  which  treatment,  however,  they  are  not 
well  adapted,  as  the  losses  are  heavy.  Ores  from  ^'i,() — 8-40  go 
to  the  cyanide  mills,  and  above  !?4()  to  the  smelters. 

•-.'.(I'.i.'-v*::^.     Gilpin  County  has  alroadj'  been  mentioned  under 
"Copper"  ('^.04. OH).    The  tj;eueral  geology  of  the  veins  is  much. 
like  that  of  Clear  Creek,  although  the  ores  are  quite  different. 

'  VV.  P.  Blake,  "The  Gold  of  Cripple  Creek,"  Eug.  and  Mia.  Jour.,  Jan- 
uary  13,  ]8i)4.  Wliitnian  Cross,  Pike's  Pejik  Atlas  Folio  of  tiie  U.  S.  Geol. 
Survey;  to  be  obt.iineil  by  seiuliiij;  '27)  cents  to  tlie  IMrec^tor  of  the  Survey, 
^Vllslli^gton,  I).  C  Kee.  Whitiiiuu  Cross  and  R.  A.  F.  Petu'ose.  Jr., 
"(Jeology  and  Mining  Industries  of  the  Cripple  Creek  Districrt,  Colorado," 
Suirnith  Ann.  Rep.  of  fhr  Diivrtov  of  flir  U.  S.  Geol  Survey,  1H<»4-1)5. 
Kcc.  W.  F.  Hillebiand,  "Chemical  Composition  of  Calaverite  from  Crip- 
])1h  Creek,"  in  Crons  and  Penrone's  Report,  p.  l!5;{.  W.  II.  llobbs,  "(>old- 
Hcliinidtite,  a  New  Mineral,"  Ainer.  ,/onr.  Net.,  May,  1890,  8.V7.  F.  C. 
Knijj,lit,  "On  the  Composition  ol"  the  Cripple  CIreek  Tellmide,"  Proc.  Colo. 
Sri  ,/(«',,  October  1,  1894.  II.  L.  McCarn,  "  Notes  on  the  (Jeology  of  the 
(idid  Field  of  Crii)j>le  Creek,  Colo.,"  Seiencc,  Jaimary  19,  1H94,  p.  31.  R. 
IVarce,  "The  Mode  of  Occurrence  of  Cold  iu  the  Cripple  Creek  District," 
I'roe.  Colo.  Sci.  Sue,  January  8,  1894;  Kny.  and  Min.  Jonr.,  March  24, 
1«94.  "  Further  Notes  on  Cripple  (Jreek  Ores,"  Proc.  Colo.  Sci.  Soe.,  April 
■'i.  1.S94.  S.  L.  I'eidield,  "Ou  Calaverite  Crystals  from  Cripple  Creek," 
Cr<).^.<  and  Penrose's  lieport,  p.  135.  E.  Skewes  and  H.  J.  Kder,  "The  Vic- 
tor Mine,  Cripple  Creek,  Colo,"  Eng.  and  Min.  Jour.,  August  19,  1893,  p. 
1!':!.  E.  Skewes,  "The  Ore  Shoots  of  I'ripple  Creek,"  Trans.  Amer.  Inst. 
Min.  Eui/.,  September,  189(3.  G.  H.  Stone,  "The  Granitic  Breccias  of 
the  Cripple  Creek  Region,"  Amer.  Jour.  Sci.,  January,  1898,  21. 


II 


306 


KEMPS  ORK  DEPOSITS. 


R.  Pearce  has  shown  the  existence  of  bismuth  in  the  ore,  and 
gives  reasons  for  believing  that  the  gold  is  in  combination  witii 
it.  Clear  Creek  County  contains  veins  on  a  great  series  of 
jointing  planes  in  gneiss  (granite),  and  in  large  part  replace- 
ments of  the  wall.  Others  are  replacements  of  porphyry  dikes 
or  of  pegmatite  segregations.  The  ores  are  chieHy  galeiui, 
tetrahedrite,  zincbleude,  and  pyrite^  and  the  gangue  is  the  wall 
rock.  The  curious  d3crease  of  value  in  depth  of  a  series  of 
parallel  veins  in  Mount  Marshall  was  earlier  referred  to 
(l.(»5.05).  Georgetown  is  the  principal  town  and  mining  center. 
Others  of  importtince  are  Idaho  Springs  and  Silver  Plume.' 

2.09.23.  Boulder  County  contains  veins  along  joints  or 
faulting  planes  in  gneiss,  or  granite,  or  associated  with  por- 
phyry dikes,  or  pegmatite  segregations,  and  carrying  tellurides 
of  the  precious  metals  more  or  less  as  impregnations  of  the 
country  rock.  The  prevalent  uountrj'  rock  is  called  by  EmuKum 
a  granite-gneiss.  Van  Diest  distinguishes  four  successive  ter- 
ranes  of  missive  and  schistose  rocks  along  three  principal  axes 
and  two  side  ones,  and  states  that  the  mines  are  on  the  sides  of 
tha  folds.  The  country  is  very  generally  pierced  by  porph}  ry 
dikes,  with  which  the  ore  bodies  are  often  associate'l,  A  large 
number  of  species  of  telluride  minerals  have  been  determined 
from  the  region,  esjiecially  bj'  the  late  Dr.  Genth,  of  Philadel- 
phia. The  mines  afford  very  rich  ores,  -somewhat  irregularly 
distributed.^ 


'  S.  F.  Emmons,  Tenth  Census,  Vol.  XIII.,  p.  70.  Rec.  F.  M.  Eudlich. 
Hatiden's  Survey,  ]8T:5,  p.  298;  IST6,  p.  IIT.  P.  Fraser,  Hnyden's  Svriru. 
1869,  p.  201.  J.  D.  Haj^ue,  Fortieth  Pdnillel  Surrei/.  Vol.  III.,  p.  r.Si). 
Rec.  R.  Peaire,  Proc.  Colo.  Sei.  Soe.,  Vol.  IIi.,  pp.  71,  210.  "The  Asso 
ciation  of  (Jokl  with  Other  Metals  in  the  West,"  Trans.  Amer.  Inst.  Min. 
Eng.,  XVIII.,  447,  1890.  Forbes  Kickaid.  "Notes  on  the  Vein  Fomiaiion 
and  Mining  of  Gilpin  County,  ("olo."  Trans.  Amer.  lust.  Min.  ling..  1  Vb 
ruary,  1898.  J.J.  Stevenson,  Wheeler's  Survey,  \o\.  III.,  j).  351.  1  .  L 
Vinton,  "Tiie  Geoij^etown  (Colo.)  Mines,"  Eng.  and  Min.  Jour..  Seiii-m- 
l)er  i:},  1879,  j).  184. 

"  Bergnth  liurkart,  "Ueher  das  Vorkommon  Verschiedener  Ti  I'lu' 
Minerale  in  den  Vereiuigten  Staaten  von  Nordamerika,"  Neues  Jahrl>"'\., 
1873,  47;;:  A,.ril,  493,  1874,  30.  Whitman  Cross,  "A  List  of  Spe<:all.v 
Noteworthy  Minerals  of  Colorado,"  Proc.  Colo.  Sei.  Soc.,  I.,  134,  1884:  '-ites 
Tellurium,  IMelornte,  Altaite,  Hessite,  Coloradoite,  Sylvaiiite,  Tellurite. 
A.  Eilens,  "A  New  Occarrem-e  of  the  Telluride  of  (Jold  and  Silver,  '  Tmiis. 
Amer.  Inst  Min.   Eng.,  I.,   31(i,  1872.     Red  Cloud  j\Iine.     S.  F.  Enniidiis, 


SILVER  AND  GOLD. 


3or 


2.09.25.     Tho  resources 
rado  are  chiefly  in  coal. 


of  the  remaining  counties  of  Colo- 


" Sketch  of  Boulder  County,"  Tenth  Census,  Vol.  XIII.,  p.  64,  IHS,").  F.  M 
Eudlich,  "Tellurium  Ores  of  Colorado,"  Eng.  and  Min.  Jour.,  XVI II,  l;i;{, 
1874.  F.  M.  Endlich,  "  Minerals  of  Colorado  Ten-itory,"  IJaifden's  Sunri/, 
1873,  352.  J.  B.  Farish,  "  Interesting  Vein  Plienoniena  in  Boulder  County, 
Colo."  (Colden  A^e  Mine),  Trans.  Anier.  Inst.  Min.  Eng.,  XIX..  .-)41.  IHOn. 
"A  Boulder  County  Mine"  (Tlie  Golden  Age  anif  Sentinel),  I'roc.  Colo. 
Sci.  Soc,  III,  316,  1H90  (same  as  above).  F.  A.  Genth,  " On  Tellurides 
from  Red  Cloud  and  Uncle  Sam  Lodes,"  Proe.  Amer.  Phil.  Sue.,  XIV., 
225,  1874.  "Tellurides  from  Keystone,  Mountain  Lion,  and  John  Jay 
Mines,"  Jde»H,  XVII.,  115,  1877.  J.  K.  Hallowell.  "Boulder  County  as 
It  Is,"  Denver,  1883.  Worthless.  N.  P.  Hill,  "  Announces  Tellurides  at 
Red  Cloud  Mine,"  Amer.  Jour.  Sei.,  V.,  ;?87,  May,  1873.  W,  F.  Hillebrand. 
" Melonite  Forlorn  Hope  Mine,  Boulder  Comity,"  Proe.  Colo.  Sei.  Soe.,  I., 
12:!,  1S84.  E.  P.  Jeimings,  "Analyses  of  Some  Tellurium  IMinerals  "  (Native 
Telliniuni  from  John  Jay  Mine;  Sylvanite,  Smuggler  Mine),  Trans.  A)iier. 
jiisl.  Mill.  Eng.,\l.,  50(5,  1877.  A.  Lakes,  "  On  Boulder  County"  Ceokigy  of 
Colorado  Ore  Deposits,  c.  1888.  A.  R.  Marvin,  "  Metamorphic  Crystalline 
Hdcks  of  the  Front  Range,"  Haj/den's  Siirrej/.  1873.  "  On  Boulder  Comity," 
pp  144,  147-152.  (185.  Map.  C.  L.  Palmer,  "Eruptive  Rocks  of  l^oulder 
County,  Colorado,"  Proe.  Colo.  Sci.  Soc.,  III.,  23(»,  1889.  C.  L.  Palmer 
and  Henry  Fulton,  "The  Quartz  Porphyry  of  Flagstaff  Hill,  Boulder, 
Colorado,"  Idem,  351,  1890.  R.  Pearce,  "Remarks  on  Cold  Ores  of 
Rrii-I;y  Jlountains,"  R.  Pearee.  In  Discus.sion  of  I'ajier  by  P.  H.  Van 
Di.st.  Proe.  Colo.  Sci.  Soe..  IV.,  349,  1893.  B.  Silliman.  "Mineral- 
ogie.il  Notes;  Tell. irium  Ores  in  Colorado."  .1  )»<(•.  .7o»?'.  Sei..  July,  1874. 
25-33.  Reprinted  in  Hmjden's  Report,  IST3,  (iHS.  J.  Alden  Smith, 
quoted  by  P.  H.  Viin  Diest  as  mentioning  Boulder  County  Jlines  in  his 
Bii'uniiil  Report  for  1880,  P.  H.  Van  Diest,  "Notes  on  Boulder  County 
Veins,"  Prae.  CoZo.  .SV'/.  aS'oc,  II.,  .50,  1880.  "The  Mineral  Resources  of 
Boulder  Coimty,  Colorado,"  Biennial  Rep.  State  School  of  Mines.  1886,  25. 
P.  il  Van  Diest,  "Evidence  Bearing  on  the  Formaticm  of  Ore  Deposits 
li\  L.iteral  Secretion ;  The  John  Jay  Mine  at  Boulder  C(mnty,  Colorado, " 
Piw.  Colo.  Sci.  Soc,  IV..  340,  18. 


mmm 


CHAPTER  X. 

SILVER    AND    GOLD,    CONTINUED.— ROCKY   MOUNTAIN   REGION, 
WYOMING,    THE   BLACK   HILLS,    MONTANA,    AND   IDAHO. 

WYOMING. 

2.10.01.  Geology. — The  southeastern  part  of  Wyoming  is 
in  the  region  of  the  Great  Plains,  the  southwestern  in  the  Culo- 
rado  Plateau.  The  Kocky  Mountains  shade  out  more  or  less 
on  leaving  Colorado,  but  are  again  strongly  developed  in  north- 
ern Wyoming.  The  northwestern  portion  contains  the  great 
volcanicdistrict  of  the  National  Park,  and  the  uor'^heastern,  a 
part  of  the  Black  Hills.  The  Cretaceous  and  Tertiary  strata 
chiefly  form  the  plains  and  plateaus.  Granite  and  gneiss  con- 
stitute the  central  portion  of  some  of  the  greater  ranges.  Pale- 
ozoic rocks  are  very  subordinate.  The  resources  in  ja-ecious 
metals  so  far  as  yet  developed  are  small,  consisting  chiefly  of 
gold  in  quartz  veins  in  the  gneisses,  ->chista  and  granites  of 
Sweetwater  County.  The  great  mineral  wealth  of  the  State  is 
in  coal.  The  iron  mines  have  already  been  mentioned  (2. 03. ( Hi), 
and  the  copper  (2. 0-4. 27).' 

'  H.  M.  Chance.  "  Resources  of  the  Black  Hills  and  Big  Horn  Countiy. 
Wyoming,"  rnnis.  Anier.  Inst.  Min.  Eiig.,  XIX.,  p.  49.  T.  B.  Conistock, 
"On  the  Geology  of  Western  Wyoming,'  Avicr.  Jour.  Sci.,  iii.,  VI.,  iJti. 
S.  F.  P^mmons,  Tenth  (\-ti.sn.%  Vol.  XHI.,  p.  8fi.  F.  M.  Endlich,  "Tlif 
Sweetwater  District,"  Haifdeu'.'i  Siirrcif,  1ST7,  p.  5;  "Wind  River  Piinjre 
Golil  Washings,  '  p.  ('(4.  A.  Hague,  "Geological  History  of  the  Yel'"w 
st<.  le  National  Park."  Trons.  Aiiicr.  Inst.  Min.  En</.,  XVI.,  78:^,  ..  1 
Yellowstone  Park  Folio,  U.  S.  (icol  Sum  See  also  F.  V.  Hayden,  Amrr. 
Jour.  Sci,  iii..  III.,  105,  I'U.  F.V.  Hayden,  AV'/..  /<)/•  1H:0-72,  p.  J;i: 
also  Anwr.  Jour.  Sci.,  ii.,  XXXI.,  '2-2!l.  A.  C.  Peale,  "Report  on  tlie 
Geology  of  the  Green  River  District.'  Haydcn's  Suri'cy,  1H77,  p.  .")11. 
Raymonds  Statistics  West  of  the.  Uockij  Mountains.  W.  C.  Knight,  BnU. 
U,  Wyo.  E.rp't  Station,  October,  1893. 


^I 


ISlLVElt  AND  GOLD,   COjVI'JN i'l-JD. 


309 


REGION, 
OAHO. 


^oming  13 
the  Ciilo- 
ore  or  loss 
i  in  nort  li- 
the great 
leasteru,  a 
lary  strata 
;neiss  con- 
es.    Pale- 
Q  jirecious 
chietly  of 
jrauites  of 
je  State  is 
(2.03.(''.i), 

rn  CoiiTiti  y, 
Conistoi'k, 
ii.,  VI.,  4-2ti. 
llich,  "Tlie 
iivor  Kiiiif-'e 
the  Yel'^w- 
1.,  TS:V  ..■  1 
tlen,  Avwv. 
0-72.  p.  13: 
[)ort  on  the 

S77,  p.  ">n. 
: night,  null. 


SOUTH   DAKOTA.— THE    BLACK    HILLS. 

2.10.02.  Geolo(jij.— The  Black  Hills  lie  mostly  iu  South  Da- 
kota. They  consist  of  a  somewhat  elliptical  core  of  granite 
and  metauiorphic  rocks,  with  a  north  and  south  axis,  and  on 
these  are  laid  down  successive  strata  of  Camhriau,  Carhouifer- 
ous,  Jura-Trias,  and  Cretaceous  rocks.  There  are  some  igne- 
ous intrusions.  The  principal  product  of  the  Black  Hills  is 
gold.  The  lead-silver  deposits  have  already  heen  described 
(2.08.18),  and  the  tin,  etc.,  will  be  mentioned  later.' 


6  543  1  22  1345 

Fig.  113. — Geological  section  of  the  Black  ITilh.     After  Flenry  Newton  Report 

on  the  lilaek  Ililb.  p.  200. 

1.  Schi.sts.    2.  Granite.    3.  Potsdam  sandstone.     4.  Carboniferous.    5.  0,  Jura  Trias. 

7.  Cretiioeous. 

2.10.03.  The  gol(^  occurs  in  stream  placers  of  Quarternary 
and  recent  age,  and  of  no  great  importance;  in  sup{)0.sed,  old 
beach  or  channel  placers  in  the  Cambrian  (so-called  Potsdam), 
conglomerates,  the  "cement"  deposits;  iu  impregnations  of  the 

'  F.  R.  Carpenter,  "Ore  De]X).sits  in  the  Black  Hills,"  Trans.  Aincr. 
Inst  Mill.  Eng.,  XVII.,  .570.  Prelim.  Bi'i).  on  the  Geol.  of  the  Black  Hill.'i. 
Rapid  City,  So.  Dakota,  1888.  \V.  O.  Crosby,  •' Geologj-  of  the  Black 
Hills."  ^o.sY.  Sac.  Nat.  Iliiit..  XXIII.,  p.  89.  P.  Frazer,  "Notes  on  the 
Northern  Black  Hills  of  South  Dakotii."  Tran.s.  Annr.  Inst.  Min.  Eng., 
XXVII.,  204,  1807.  John  D.  Irving,  "A  Contribution  to  tlie  Geology  and 
Ore  I )cposits  of  the  Northern  Black  Hills.  South  Dakota,"  Annals  X.  Y. 
Anitl.  Scicnees,  XII.,  Partll..  18!l'J.  Kec.  Newton  andJenney,  Report  on 
the  Black  Hills,  Washington,  1880.  F.  C.  Smith,  "The  Occurrence  md 
Bt'liiivior  of  Tellurium  in  (Jold  Ores,  nmrc  ixirticuiarly  witii  Referen'-e  to 
tlie  Potsdam  Ores  of  the  lilack  Hills,"  Tnins.  Anier  Inst.  Min.  Eng.. 
XXVI.,  485,  11  .,  189(5.  '•  Tlie  Potsdam  (iold  Ores  of  the  Black  Hills  of 
Soiitli  Dakota,"  Idem.  XXVII.,  40|.  428,  ls!t7.  Rec.  C.  R.  Van  Hise. 
"The  Pre-Cambriau  Rocks  of  tiie  Black  Hills,'  Bull.  Geol.  Soc.  Anier.,  I., 
20.S-244.  N.  n.  Winchell,  "Report  on  the  Black  Hills,"  AV^j.  Chief .  of 
U.  S.  Engineers.  1874,  Part  II.,  p.  <>:{().  The  U.  S.  Geological  Survey  is 
I'rpparing  a  report  on  the  Black  Hills,  S.  F.  Enunous  and  T.  A.  Jaggar 
being  in  charge  of  the  work. 


310 


KEMP'S  ORE  DEPOSITS. 


Cambrian  lime-shales,  with  siliceous  gold  ores  in  the  neigh- 
borhood of  intruded  dikes  and  sheets  of  phonolite;  increvicpsjn 
the  heavy  Carboniferous  limestone,  now  filled  with  siliceous 
gold  ores;  and  in  broad  zones  or  fahlbands  of  Algonkian  slaty 
and  mica  schists,  carrying  auriferous  pyrites.     The  above  are 


CAABONIFtROUS     IIMCSTONK 


riNK  IIMCSTONC 


CAMBKIAM    'HAIU 


AlCONKIAN   SLATES,   tUARTZITCS  (tCt 


Fig.  114. — (leolinjicnl  ncction  i<f  the  strata  in  the  Northern  Black  Hills,  S.  D. 
After  John  I).  Jrrinf/,  Ainialis  of  the  Xeir  York  Academy  of 
Seienee.%  XIL,  Part  II.,  1899. 

found  in  the  northern  Hills.  In  the  central  portion  pegmalites 
have  recently  proved  gold-bearing.  The  Quarternary  and  rcwnt 
gravels  were  effective  in  attracting  prospectors  in  the  ''arly 
days  of  settlement.  They  are  scarcely  worked  to-day.  Tbo 
aucient  beach  gravels  are  still  followed  beneath  the  caps  of  por- 
phyry in  some  small  mines  in  Deadwood  Gulch.     As  desciibed 


''"ii'irM. 


SILVER  AND  GOLD,   CONTINUED. 


;ui 


by  W.  B.  Devereux  iu  1S8'2,  the  gravels  were  regarded  as  hav- 
iug  derived  their  gold  by  the  beating  of  the  waves  of  the  Cam- 
bi  inn  Ocean  against  the  auriferous  schists  described  below,  but 
laior  work  has  made  it  probable  that  tbey  are  impregnations 
like  the  Potsdam  siliceous  ores.  The  pay  gravel  now  runs 
as  a  shoot  under  the  later  lava  sheets.  The  impregnations  of 
the  Cambrian,  locally  called  Potsdam,  lime-shales  with  tellu- 


AHS.   ftUARTZITtS  ttft 


Cambrian  Shale 
anil  Siiiidiock. 
(Very  Calcar«oua) 

Cambrian  Quartzile 
and  Conglomerate 
("Cement") 


'  AljioDkfan 


Cross  SECTIO^•  of  Ore  Chute. 


I'l..  X  or  ()i!i:  CiiuTE, 

The  ore  is  isuokkn  awat 

to  .<1i0ay  the  verticals. 

Fio.  WT^.—Plnn  and  ci'oss-section  of  a  Camhrinn,  silieeons  gold-ore  deposit  in 
the  Black  //ills,  S.  D.     After  John  D.  Irving,  Annals  N.  Y. 
Academy  of  Sciences.  XIT.,  Purf  //.,  1899. 

rides  and  pyrites,  constitute  a  form  of  ore  body  that  has  been  of 
rather  recent  development,  but  that  is  now  the  leading  producer. 
Tiie  mines,  as  indeed  nearly  all  the  gold  developments,  are  in 
tlie  northern  Hills,  and  are  especially  abundant  around  Terry 
Pt'j^k.  The  Cambrian  lies  flat,  and  is  penetrated  very  abun- 
dantly by  dikes  and  sheets  of  trachyte  and  pbonolite.     The  ig- 


312 


KEMP'S  ORE  DEPOSITS. 


neons  rocks  have  themselves  sometimes  been  impregnated,  when 
they  lie  near  an  ore  body.  Associated  with  the  ore  shoots  ami 
usually  bisectin<j;  that  portion  of  the  floor  that  lies  beneath  them 
are  found  cracks,  called  "verticals,"  that  run  down  to  unknown 
depths,  but  that  are  not  accompanied  by  any  notable,  if,  in- 
deed, by  any  appreciable  faulting.  The  verticals  have  di- 
rected, or  have  served  to  introduce  the  solutions,  which  have 
then  spread  laterally  into  beds  of  lime-shales  and  have  replaced 


•^    I.iii...  .str.-,Tc» 


=^^8- 


.      +  +  ■«.  + +  +  +  4.+4  +  4-  +  -* +  4-  +  -t-^f+ ■4-4  +  4  4-4- +  +•4-^4■^ 
+  +  +-»-  +  -H-t--t-  +  +  +  f  +  +  -f--H--h  +  +  -f-H-f  +  4  4-++-i-+  +  +  +  +  4- 

l+-«-+-t--t-f+-*+-f  +  .t-  +  +  +  4.i  oipnji>  +  ^.+.4.^.^.^.^.^.^^.  ^.^.+  ^+^.+^_ 

+  +4*  +  +  -t-f-*-  +  -t+  "*^ +■  "*■  +^_+;_j-^-*- -^  +  -|-t-+-t+  +  +-«-*  ,-4. +-4-4-  +  +4  +  +  J.  +  +  ' 


bKCTiuN  A-B. 


Fig.  llfi. — Plitn  luid  sertion,  Mail  and  Express  Mine,  to  ifhistratc  (hi'  silicenu 

gold  ores  of  till'.  lHaek  [filln,  S.   /),     Aftiv  Jnhii   /).  frrin;/,  .in  mils 

iV.    )'.  Aradniii/  of  Si-ieiiri's.  XII.,  Pn rt  II.,  iSitU. 

the  calcareous  portion  of  them  with  ore  and  silica.  Those  bods 
of  lime-shales  have  proved  most  favorable  which  rest  upon  a 
floor  of  hard  quartzite,  and  this  association  is  so  constant  that 
the  miners,  in  regions  of  phonolite  sheets,  sink  to  the  quartzite, 
and  then  explore  for  ore.  The  ore  runs  in  long  shoots  on  the 
strike  of  the  verticals. 

The  ores  contain  as  gangue  quartz,  fluorite  and   the  ujue- 
placed  residue  of  the  lime-shales.     The  metallic  minerals  are 


Flo.  117. — Green  Moimtain,  Bhiek  Hills.  SJ)  ;  d  UieeoUteof  plioiioUle,  xritli 

the  mines  of  silieeuns  ore  on  the  so  cdllcd  "  npper  eontaet  "  around 

its  foot.     I'Jtofoyraphed  l>jj  Jolin  D.  Iri'ing,  1808. 


(  IKlls 


the  imwr 
lerals  are 


Fut.  118.  —  \'iew  of  tli:'  Union  Mine,  in  siliceous  ore,  netir  Terrij,  in  the 
BIdek  [fills.  S.  D.     Phototjraphed  l)y  John  D.  Irving,    181)8. 


SiLTPKois  r.oT.n  Our 

IN  I.IMKSTONK. 


slmw  iri^;  Silit  ilii  iil'iDn 
of  IfM'i'i'iatfd  LiiiR'Mone  nnd 
ini-  1)1'  i]i-lii:ir<-ntiuii  lii'twi'tn 
llif  Oivarnl  Wall-lmk 


Tvi'K  OK  IvAdOKD  Top  Ykutical 

IN  CAIiliOMl'KKOlS  J^ I M KSTON H 
ON  DaCY  I'l.AT 

Lawiiknce  Co. 
SorTii  Dakota. 


FUi.  I'iO. — I'crspcctm'  croNN-sccdiHi  of  siliccons  yohl  ore  in  ('<trht)iiif(ro)i.i 

liinestoiie,  D((('y  Flat,  lilavk  Ililh.    After  John  I).  Irriinj.  .[luuils 

N.  y.  Academy  of  SciciKrs.  XII..  Pari  II..  is'.tit. 


Fio.  121. — View  of  the  (iolilcit  St<iroi)cii  cut.  Lead  Citi/.  S.  D.     From 
a  photograph  by  J.  F.  Keiiq),  1890. 


SILVER  AND  GOLD.  CONTINUED. 


313 


in' 

,ili»->liilK-  aii.l 
itloll  liul^ri  II 

iiU-iotk 


JSTOXE 

)akota, 

•boiiifrroiia 
Aniiiilti 


^':-d 

),     From 

jjyrite  and  a  supposed  telluride  of  gold,  -whose  presence  is  indi- 
cated by  analysis,  but  ■which  has  not  beo>n  actually  seen.  Tho- 
rium has  also  been  detected  by  F.  C.  Smith.  There  are  two 
varieties,  red,  or  oxidized,  ores,  and  blue,  or  unoxidized.  Tliey 
are  collectively  known  as  siliceous  or  Potsdam  ores.  The 
presence  of  tellurium,  of  fluorite,  and  of  phouolite  is  highly 
suggestive  of  Cripple  Creek,  Colo.,  and  of  several  newer  dis- 
tricts in  Montana.  At  times  the  vertical  may  lie  alongside  of 
HU  intruded  dike  as  shown  in  Fig.  Ill*,  and  then  the  ore  fol- 
lows the  dike  and  may  impregnate  it  more  or  less. 

The  intruded  igneous  rocks  have  seldom  been  able  to  pierce 
the  heavy  cap  of  Carboniferous  limestone,  but  tlie  laccolites 


Fig.  119. — Crosit-sernon  of  a  siliceous  gold-ore  hmli/  h/iiiy  next  to  a  propJujry 
dike.  Black  IliUn,  S.  D.     After  John  I).  Inniuj,  Annals  N.  F. 
Academy  of  Sbiena..,  X/I,  Part  II.,  1899. 

have  served  to  dome  it  up,  and  to  fissure  it  more  or  less.  In 
tb(3  vicinity  of  the  Ragged  Top  laccoliup,  on  Dacy  Flat,  these 
fissures  or  crevices  have  been  the  seat  of  the  deposition  of  rich, 
siliceous  ores.  The  ores  have  replaced  and  cemented  into  a 
hard  aggregate,  the  brecciated  limestone  that  filled  the  fissure 
before  their  introduction.     (See  Fig,  1"^0.) 

The  older,  and  formerly  the  chief  source  of  gold  in  the  Black 
Hills,  is  in  the  great  zone  or  fahlband  of  schists  near  Lead  Cit}', 
which  carries  little  lenses  and  veinlets  of  quartz,  with  aurifer- 
'uis  pyrites.  The  pay  is  thought  to  lie  in  the  schists.  The  ores 
are  free-milling,  and  are  controlled  b}'  the  Honiestake  Com- 
pany.    They  are  situated  in  and  near  Lead  City,  in  hills  which 


;5I- 


KKMl'S  ORE  Din'OSITS. 


form  steep  divide.s  between  the  narrow  gulches.  The  schistH 
strike  about  N.  'iO  W.,  and  dip  «i()  E.,  and  in  the  Golden  Star 
are  stoped  out  in  a  cross-section  over  450  feet.  Porphyry  dikes 
cut  the  KchistH,  and  have  spread  laterally,  so  as  in  their  present 
eroded  condition  to  appear  like  surface  caps  of  lava.  They  nia\ 
have  exercised  an  important  influence  in  the  enrichment  of  tlio 
schists,  but  it  seems -certain  that  gold  was  present  in  them  in 
the  Cambrian  times,  because  the  Cambrian  sediments  when 
carefully  panned  almost  always  afford  some  trace  of  the  yellow 
metal.  The  special  local  enrichment  of  the  schists  may  have 
been  influenced  by  the  porphyry.  The  ores  are  low  grade,  run- 
ning $.'J — 84  or  less.  The  Old  Abe,  Golden  Star,  Dead  wood- 
Terra  and  Father  de  Smet  are  the  chief  locations.' 

In  addition  to  the  types  of  ore  body  described  above,  there  are 
found  throughout  the  schists  of  the  Hills  occasional  quartz 
veins,  of  the  old  so-called  "segregated"  variety,  that  have 
yielded  a  little  gold.  Recently  pegmatites  near  Harney  Peak 
have  proved  productive,  affording  ores  similar  in  their  geology 
to  those  described  by  Hussak  from  Ouro  Preto,  Brazil,^  and 
to  some  in  the  Transvaal. 

MONTANA. 

2.10.04,  Geology. — The  eastern  part  of  the  State  belongs  to 
the  region  of  the  Great  Plains,  which  is,  however,  in  portions 
greatly  scarred  by  erosion,  forming  the  so-called  Bad  Lands. 
The  approaches  to  the  Rocky  Mountains  are  not  abrupt  and 
sudden  as  in  Colorado,  but  are  marked  by  numbers  of  outlying 
ranges  of  both  eruptive  and  sedimentary  rocks.  The  chain  of 
the  Rockies  takes  a  northwesterly  trend  in  Wyoming,  and  so 
continues  across  Montana.  It  is  rather  the  j)rolongation  of  thy 
Wasatch  than  of  the  Colorado  Mountains,  whose  strike  is  for 
the  Black  Hills.     The  character  of  the  ranges  is  also  very  dif- 


'  A.  J.  Bowie.  "Notes  on  CJold  Mill  Construction,"  Tvans.  Amer.  I)ist. 
Mill.  Eiuj.,  X.,  ST.  1881.  W.  B.  Devereux.  "Tlie  Owuirence  of  Gold  iu 
the  Potsdam  Formation,"  Idem,  X..  4()r);  Eiig.  and  Mhi.  .loiir.,  Dcjeiiihcr 
2:{,  1883,  p.  .334.  H.  O.  Hoffman,  "Cold  Mining  in  the  Black  Hills," 
Trann.  Aincr.  Tiist.  Miii.  Eng.,  XVH.,40M:  alsoin  i)rt'liminary  rejmrt  citi'd 
•inder  Carpenter,  under  Geology.     See,  in  addition,  references  on  page^K'i*. 

*  E.  Hussak,  "Der  Roldfiihrende,  kiesige  Quarzlajcergang  von  Pa.ssap'iu 
in  Minas  Geraes,  Brasilien,"  Zeits.  fur  prakt.  Oeologie,  October,  1898,  'M'). 


.siI.VHIi   AM)  (iOl.n.   ('<)XTINUED. 


316 


Bcliists 
ill  Star 
■f  (likt's 
present 
oy  iHiiy 
b  of  tho 
bhem  in 
s  when 
)  yellow 
ay  liHVo 
,(]e,  run- 
id  wood- 

ihere  are 
il  quartz 
lat  have 
ley  Peak 
•  geology 
izil,''  and 


elongs  to 

portions 

Lauda. 

irupt  and 

outlying 
3  chain  of 

g,  and  so 
ion  of  tbo 
rike  is  f<'r 

very  dif- 

Amev.  Lixf- 

of  Gold  in 

l)e';einli<'i" 

iu-k  Hills" 

report  citi'il 

m  rassapt'iii 
T,  1898,  84.-.. 


fereut.  They  are  lesH  elevated,  and  have  broad  and  wtdl- 
watered  valleys  between,  that  admit  of  eonsiilerable  agricul- 
ture. Geologically  the  country  is  in  niarkel  contrast  witli  Col- 
orado. While  in  the  latter  the  lower  J'aleozoic  is  feebly  devel- 
oped, in  Montana  it  is  important.  Special  interest  attaches  to 
the  Lower  Catnbrian  or  perhaps  pre-Cambriau  (piartzitos  and 
associated  sediments  that  are  present  in  great  thickness  in  the 
northwestern  part  of  the  State,  and  along  the  Idaho  line.  Fos- 
sils have  recently  been  reported  by  C.  D.  Walcott  from  a  very 
low  horizon.  On  the  east  of  the  Continental  Divide  the 
gneisses  and  schists  of  the  Arcbean  are  succeeded  by  metamor- 
pliosed  sediments  of  the  Algopkian,  involving  7,(>()()  feet  or 
mure,  and  known  as  the  Cherry  Creek  formation  of  the  U.  S. 
Geologists.  Unconformably  upon  this  lies  the  Belt  formation, 
of  •),()()()  to  1(1,(1(10  feet  of  sediments,  which  are  doubtfully  re- 
ferred to  the  Algonkian.  Still  above  come  the  true  Cambrian, 
I. (•()(/  to  1,50(1  feet;  Siluro-Devonian  (of  which  the  latter  alone  is 
iileutified  by  fossils),  200  to  (iOO  feet;  Carboniferous  limestones, 
sooto  1,000  feet,  followed  by  a  ipiartzite  and  shale  series  of  200 
to  (iOO  feet;  Jura-Trias  up  to  .500  feet;  and  then  some  thou- 
sands of  feet  of  Cretaceous  and  Tertiary.  Great  hatholites  of 
granite,  in  part  at  least  post-Carboniferous,  have  been  intruded 
as  set  forth  earlier  under  Butte,  2.04.0.').  They  have  basic  phases 
on  the  margins,  and  locally,  within  the  masses,  as  at  Butte. 
The  above  grouping  modifies  somewhat  the  section  given  in 
earlier  editions  of  this  work,  and  has  resulted  from  the  more 
recent  work  of  W.  H.  Weed  and  A.  C.  Peale  of  the  U.  S.  Ge- 
ological Survey,  whose  folios  should  be  consulted  for  local  de- 
tails so  far  as  available.  East  of  the  main  chain  of  the  Rock- 
ies there  are  peculiar  isolatetl  groups  of  mountains  of  a  lac- 
I'olite  character,  such  as  the  Highwoods,  the  Judith,  and  the 
T.ittle  Rockies.  They  rise  like  huge  blisters  of  sedimeutaries, 
forced  up  by  lenticular  sheets  of  intrusives,  and  pierced  by 
dikes  in  vast  numbers.  They  are  rocks  prevailingly  rich  in 
.«o(ia,  and  present  many  rare  and  interesting  types  and  some 
striking  parallels  with  the  Black  Hills.' 

'  8.  Calvin,  "Iron  Bvitte:  Some Preliminaiy  Notes,"  ^wc/-.  Geol,  IV.,  95. 
<•  E.  Culver,  'A  Little  Known  Region  of  Northwestern  I\Ioutiina,"  Wis. 
Arad.  of  Sci.,  December  '60.  t891.  W.  M.  Davis,  "The  Relation  of  the  Coal 
i!  Montana  to  the  Oldor  Rocks."  Tenth  Census.  Vol.  XV.,  p.  097.     Rec. 


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KEMPS  ORE  DEPOSITS. 


2.10.05.  Montana  ook  the  lead  of  all  the  States  in  1887  in 
the  production  of  silver,  was  second  in  gold,  and  first  in  the 
total  production  of  the  two.  It  is  now  second  to  Colorado  in 
silver,  and  fourth  on  the  list  in  gold,  hut  in  copper  it  is  first. 
In  its  mineral  wealth  it  yields  to  no  other  State  in  the  Union. 
The  mining  districts  are  mostly  in  the  western  central  and 
western  portions.  Developments  have  progressed  so  rapidly 
that  all  the  desirable  data  are  not  available. 

2.10.00.  Madison  County.  The  chief  product  is  gold.  Near 
Virginia  City  the  gold-bearing  quartz  forms  veins  in  schists; 
in  the  northeastern  part  of  the  county  the  veins  occur  in  gran- 

J.  Eccles,  "On  the  Mode  of  Occurrence  of  Some  of  the  Volcanic  Rocks  of 
Montana,"  Quai:  Jour.  Oeol.  ScL,  XXXVII.,  39!).     G.  H.  Eldriage,  "Mon 
tana  Coal  Fields,'  Tenth  Census,  Vol.  XV.,  p.  739.     S.  F.  Emmons,  Tenth 
CensMs,  Vol.  XIII.,  97.     Rec.     Hai/den's  Survey,  Ann.  Eep.,  lS~l-72.    J. 
F.  Kemp,   "On  Tellurides  in  Montana,"  see  The  Mineral  Industry,  \I., 
312,  1S98.     W.  S.  Keyes,  in  Brown's  fir.st  rei)oit  on  mineral  resources,  etc., 
last  part,  Amer.  Jour.  ScL,  II.,  46,  481.     Rec.     W.  Ijndgren,  "Eruptive 
Rocks,"  Tenth  Census.  Vol.  XV.,  p.  V19,  forming  A])pendix  B  of  Davis's  first 
paper.'   See  also  i*roc.  Ccd.  Aead.  Set'.,  Second  Series,  Vol.  III.,  p.  39.     J.  S. 
Newberry,  "Notes  on  the  Surface  Geology  of  the  Country  Bordering  on 
the  Northern  Pacific  Railroad,"  Annals  N.  Y.  Acad.  Sei,  Vol.  III.,  342; 
Amer.  Jour.   Sci.,  iii.,  XXX.,   337.     "The  Gn«it   Falls  Coal   Fields,"  in 
Geol.  Notes,  School  of  Mines  Quarterly,  VIII.,   327.     A.  C.  Peale,  Tiiree 
Forks  Folio,  U.   S.   Geol.    Surrey,   1896.     Rec.     F.  Rutley,    "  Microscojuc 
'Character  of  the  Vitreous   Rocks  of  Montana."  Quar.  Jour.  Geol.  Sei., 
XXXVII..  391.     See  Eccles,  above.     CD.  Walcott,  "  Pre-Cambrian  Fos- 
siliferous  Formations,"  Bull.  Geol.  Sac.  Amer.,  X.,  199,  1899.    Rec.    W.  II. 
Weed,  "The  Cinnabar  and  Bozeman  Coal  Fields  of  Montana,"  idem,  II.. 
349-3()4      Eny.   and  Min.   Jour.,  May  14  and  21,  1892.     "Montana  Coal 
Fields."   Bull.   Geol.  Soc.  Amer.,   III.,  301-330,     Livingston   Folio,  U.  S. 
Geol  Survey.     Butte  Special  Folio,  Idem;  Little  Belt  Folio,  Idem;  Brill 
Folio  (in   prepanition).     Weed  and  Pirsson,    "Highwood   Mountains  of 
Montana," /?«//.   Geol.  Soc.  Amer.,  YJ,  iiSQ,  189.").     "The  Bearpaw  Moiui- 
tains  of  Montana,  Amer.  Jour.  Sci.,  May,  1896,  283;  June,  ]).  301;  Septem- 
ber, p.  136;  Octol)er,    p.    188.     "Geology   of  the  Little  Rocky  Mountains." 
Jour.  Geol,  IV.,  399.      "The  Castle  Jlountain  Mining  District,"  Bulletin 
139,  U.  S.  Geol.  Survey,  1896.     "The  Judith  Mountains,"  Ann.  Rep.  Dir. 
U  S.  Geol.  Survey.  XVIII.,  1899,  Part  III.,  437.     All  these  are  Rec.     R.  P. 
W^hitUeld,  "Li.st  of  Fossils  from  Central  Montana,"  Tenth  Census,  Yo). 
XV^,  p.  712;  Apiiendix  A  to  Davis's  paper.     J.  E.  W^olff,  "Notes  on  the 
Petrography  of  the  Crazy   Mountains,"  etc.,    Norther)i    Tnois.    Survey. 
"Geology  of  the  Crazy  Mountains,"  Bull.  Geol.  Soc.  Amer..  III.,  44.5.     H. 
W<K)d.  "Flathesid  Coal  Basin,"  Eny.  and  Min.  Jour.,  July  16,  1892,  p.  'u. 
H.  R.  Wood,  "Mineral  Zones  in  Montana,"  Idem,  September  24,  1892,  p.  292. 


SILVER  AND  GOLD,   VONTINUED. 


317 


ite;  at  Rochester  the  gold  is  associated  with  galena;  at  Sheri- 
dan tetrahediite  and  chalcopyrite  are  found  in  quartz  veins  and 
are  rich  in  gold  and  silver.^  An  interesting  vein  with  tellur- 
ides  has  been  discovered  at  the  Mayflower  mine  in  the  Tobacco 
Root  Mountains.^  It  is  a  fault  fissure  nearly  parallel  to  the 
bedding  of  upturned  Cambrian  limestones.  The  ore  has  re- 
placed the  limestone  and  is  largely  oxidized.  Placers  were  of 
extreme  importance  in  this  county  in  early  days,  and  are  still 
somewhat  worked.  Alder  Gulch,  near  Virginia  City,  proved 
extraordinarily  rich, 

2.10.07.  Beaverhead  County.  Near  Bannack  City  quartz 
veins  with  auriferous  pyrite  on  the  contact  between  the  lime 
stone  and  so-called  granite.  At  Glendale,  in  the  northern  part 
of  the  county,  are  the  Hecla  mines,  referred  to  under  "Lead- 
silver"  (Example  32).  Auriferous  (juartz  veins  are  reported 
farther  north.'' 

2.10.08.  Jefferson  County.  There  are  many  varieties  of  ore 
bodies  in  this  county,  but  the  commonest  type  is  similar  to  that 
at  Butte,  i.e.,  veins  in  granite  along  fissures  of  slight  displace- 
ment. The  ore  is  altered  country  rock,  which  is  mineralized 
with  quartz,  pyrite,  arsenopyrite  and  galena.  Rich  sulphides 
of  silver  have  been  met  in  the  upper  portions.  The  Alta  mine 
near  Wickes  was  located  on  a  vein  in  andesite.  The  Ruby 
mine,  on  Lowland  Creek,  appears  to  be  a  chimney  of  boulde^-s 
of  rhyolite,  which  are  coated  with  gold-bearing  silver-sul- 
jiliides.  It  resembles  the  Bassick  mine  of  Colorado  (2.0U.20) 
iu  geological  relations.  One  of  the  largest  mines  yet  opened 
ill  the  county  is  the  Elkhorn.  The  ore-deposits  resemble  the 
"saddles"  of   the  Bendigo  Field,  Victoria,  Australia.*     They 

'  For  these  notes  the  writer  is  especially  indebted  to  Mr.  W.  H.  Weed, 
of  the  U.  S.  GeoU)gical  Survey.  See  also  S.  F.  Emmons,  Tenth  Census, 
XUl.,  97.  Tlie  northeastern  portion  of  Madison  County  has  been  majiped 
by  A.  C.  Peale — Tlu-ee  Forks  Folio,  U.  S.  Geol.  Survey  -by  whom  are  also 
given  notes  on  the  mines      Rec. 

"  R.  Peanw,  "Notes  on  the  Occurrence  of  Tellurium  in  an  Oxidized 
Form  in  Montana,"  Proc.  Culo.  Sci.  Soc,  November  2,  IS'Jfi. 

'S.F.  Emmons,  Tenth  Census,  XUL,  97.  R.  W.  Barrell.  "  Tlie  Min- 
eral Formation  at  the  Golden  Leaf  Mines,"  Eng.  and  Min.  Jour.,  July  17, 
18!)7,  64. 

*  E.  J.  Dunn,  "Quarterly  Report  to  the  Mining  Department  of  Victoria, " 
December,  1888.  T.  A.  Rickard.  "  The  BendigoGold  Field,"  Trans.  Auier 
Inst.  Min.  Eng.,  XX.,  4(5;{,  ISdl. 


318 


KEMP'S  ORE  DEPOSITS. 


occur  along  the  contact  of  Cambrian  slate,  and  underlying  lime- 
stone, and  are  replacements  of  the  limestone  at  the  crests  of 
shattered  anticlines.  The  ores  are  silver  sulphides  in  a  quartz 
gangue,  but  with  occasional  large  bunches  of  galena,  and  very 
beautiful  crystals  of  calamine,^ 

;^.  10.01).  Silver  Bow  County.  The  mines  around  Butte  aro 
the  chief  if  not  the  only  ones  of  the  county.  Their  general  ge- 
ology and  distribution  will  be  found  described  under  "Copper" 
— in  connection  with  the  copper  veins,  and  a  map  is  there  given 
of  the  local  geology.  The  silver  veins  surround  the  copper 
ones  on  the  north,  southwest  and  west.     Their  geological  rela- 


YrJ,  <^^) 


8 


a  8        4  6  a  7 

Fia.  124. — (h'088  section  af  vein  at  the  Alice  mine,  Btitte,  Mont.     Tlie  mdVi  of 
vein  is  iO  feet.    After  W.  P.  Blake,  Ivans.  Ame;'.  Inst.  Mln.  h'ng., 

XVI,  p.  ".2. 

1.  Granite  country.  2.  Softened  granite  witli  siiiall  veins.  '.).  Clay  wall  with  decomposed 
granite.  4.  Q:iMrtz,  broken  and  seamed.  .I.  Clay  and  deedniposi'd  );i-.iiiite.  0,  Quartz  and 
manganese  spar — "  curly  ore."  7.  Quartz  and  ore — "  hard  vein."  8.  Soft  granite  with  vein- 
ets.    '. .  Hard-colored,  hard  granite  of  the  hanging-    all  country. 

tions  and  character  are  much  the  same,  but  in  mineralogy  and 
distribution  they  are  different.  The  silver  veins  occur  both  in 
the  basic  (Butte)  granite,  and  in  the  acidic  (Bluebird)  granite. 
They  contain  as  gangue  in  addition  to  quartz,  manganese  com- 
pounds, rhodonite  and  rhodochrosite.  The  outcrops  of  the 
veins  appear  as  blackened  ledges  of  quartz,  the  stain  being  due 
to  manganese  oxides.  The  ores  are  sulphides  of  silver,  galena, 
blende  and  pyrite,  with  almost   no  copper  minerals   whatso- 


•  The  above  notes  were  chiefly  furnislted  l>y  "Sir.  W.  H.  Wet;d.  See  also 
S.  F.  Emmons,  Tenth  Census,  Vol.  XTII.,  j).  07.  J.  .S.  Newberry,  'Ou 
Red  Mountain,"  Annals  N.  Y.  Ac(i<l.  Sci.,  ITI.,  ]>.  *251. 


Fig. 


g  lime- 
■ests  of 
quartz 
id  very 

Litte  aro 
era I  ge- 
;jopper" 
:e  giveu 
a  copper 
cal  rela- 


Tho  widVi  of 

ElHJ., 

ilt'composed 
0,  yuurtz  and 
uite  Willi  veiii- 

alogy  ami 
nr  both  iu 
)  granite. 
lu'se  coin- 
ips  of  tlie 
l)eiug  tine 
er,  galena, 
s  whatyo- 

d.     See  also 
,■  berry,   "<"i 


Fig.  122. — Oiitwop  of  tlw  Wabnuli  siln-r  h»lr.  jirojeeting  tibovc  tin'  (jranite, 
Butte,  Monfdnit.     From  a  photoijraph  by  A.  ('.  Bcatty.  18'J6. 


—Weathered  granite,  Butte,  Montana.     The  bouldem  are  due  to 
the  rounding  off  of  ttlockn,  produced  by  joints.     From  a 
phoiograph  by  J.  F.  Kemp,  1896. 


SILVER  AND  GOLD,   CONTINUED. 


319 


ever,  except  along  the  border  between  the  copper  territory  and 
the  silver.  The  veins  display  recognizable  banding  of  ore  and 
giingue.  One  series  of  locations  embracing  the  Moulton,  the 
Alice  and  the  Magna  Charta,  has  been  called  the  Rainbow  lode 
hy  J.  E.  Clayton  from  its  crescentic  sweep. 

In  other  respects,  as  regards  faults,  relation  to  the  walls 
and  general  origin,  the  remarks  already  recorded  under  "Cop- 
per" will  hold  good. 

Auriferous  gravels  were  early  washed  in  the  valley  of  Silver 
Bow  Creek,  and  led  to  the  discovtry  of  the  deep  veins.' 

3.10. 10.  Broadwater  County  has  recentl}'  been  organized,  and 
contains  quartz  veins  in  slates  near  Winston,  and  auriferous 
pyrites  in  shattered  granite  at  the  Diamond  Hill  mines, 
(iranite  County,  formerly  a  part  of  Deer  Lodge,  has  important 
mines  near  Phillipsburg.  The  Granite  Mountain  mine  is 
located  on  a  fissure  vein  in  granite,  and  yielded  rich  silver 
ores,  with  considerable  gold.  The  vein  adjoins  sedimentary 
rocks,  which  are  much  metamorphosed  by  the  granite. "^ 

3.10.11.  Deer  Lodge  County.  Placers  are  numerous  along 
the  Deer  Lodge  River,   and  auriferous  quartz  veins  are  not 


'  Tlie  Butte  Siiecial  Folio  of  the  U.  S.  Geological  Survey  is  the  best  work 
of  reference.  It  is  by  W.  H.  Weed,  S.  F.  Euimons,  and  (Jeo.  W.  Tower. 
W.  P.  Blake,  "Silver  Mining  and  Milling  at  Butte,  ]\Iont.,"  Traun. 
Anwr.  Inst.  Min  Eiig.,  XVI.,  ;J8.  "Rainbow  Lode,  Butte,  Mont.," 
J'li'iii,  XVI.,  65.  Rec.  R.  G..^Brown,  "The  Ore  Deix)sits  of  Butte  City," 
Idem,  XXIV.,  54:),  1894.  Rec.  S.  F.  Ennnoas,  "Notes  on  the  Geolo- 
gy of  Butte,  Mont.,"  Idem.,  XVI  ,  49.  C.  W.  Goodale,  "The  ('o!i- 
ceiitration  of  Ores  in  the  Butte  District,  IVIontana,"  Idem,  XXVI.,  599, 
MH).  Richard  Pearce,  "The  Associations  of  Minerals  in  the  Gagnon 
Vein,  :  utte  City,"  Trans.  Amer.  Inst.  Min.  Eng.,  XVI.,  63.  F.  D.  Peters, 
M!u>>ml  Resources  of  U.S.,  1888-84,  p.  374.  E.G.  Spilsbury,  "Placer 
Mining  in  Montana,"  Eng.  and  Min.  Jour.,  September  3,  1887,  p.  167. 
Kec.  "  Silver  Mines  of  Butte,  Mont.,"  Ibid.,  Aoril  18,  1885,  p.  261.  Wil- 
iiaiiisand  Peters,  on  Butte,  Mont.,  Eng.  and  Min.  Jour.,  March  38,  1885, 
p.  208.     See  also  references  under  Butte  Copjxir. 

"  H.  M.  Beadle,  "The  Condition  of  the  Mining  Industrj'  in  Montana  in 
\X'.y2."  Eng.  and  Min.  Jour..  Felmary  11,  1893,  p.  133.  W.  H.  Dodds, 
■Granite  Mountain  Mine,"  Collier)/  Engineer,  December,  1893.  G.  W. 
Goodale  and  W.  A.  Akers,  "Concentration,  etc.,  with  Notes  on  the  (i eol- 
oL'y  of  the  Flint  Creek  Mining  District,"  Trans.  Amer.  Inst.  Min  Eng., 
XVIIl.,  343,  1890.  Rec.  "The  (Granite  Mountain  Mme."  Eng.  and  Min, 
Jour.,  December  10,  1887;  November  33,  1889. 


I        >\ 


m!M 


j;ar, 


820 


KKMP'S  ORE  UEPOSITS. 


IIEtl! 


In 


lacking.  In  the  extreme  eastern  part  are  the  veins  of  tb(> 
Bald  Butte  group  in  slates  and  intrusive  diorite.* 

2.10.1'^,  Lewis  and  Clarke  County.  The  placer  mines, 
near  Helena  (in  Last  Chance  and  Prickly  Pear  gulches),  were 
the  first  in  the  county  to  attract  attention.  They  were  found 
by  the  prospectors  who  spread  through  the  Rocky  Mountains 
as  the  California  gold  diggings  gave  out.  Since  then  many 
auriferous  quartz  veins  in  granite  and  slates  have  been  devel- 
oped.  Some  twenty  miles  north  of  Helena,  in  the  town  of 
Marysville,  is  the  Drumlummon  group  of  veins,  which  carry 
refractory  silver  and  gold  ores,  in  a  quartz  gangue,  on  the  con- 
tact between  a  diorite  boss  and  the  surrounding  metamorphic 
schists.  There  are  also  other  veins  in  the  granite.  Dikes  of 
intrusive  rocks  occur  associated  with  the  ore  bodies.'* 

3. 10. 13.  Meagher  County  contains  the  Castle  Mountain  min- 
ing district,  once  the  heaviest  producer  of  silver-lead  ores  in 
the  State.  The  Castle  Mountains  embrace  a  geological  section 
from  and  including  the  Algonkian  to  the  present.  Intrusions  of 
granite,  diorite,  various  porphyritic  rocks  and  surface  flows  of 
considerable  petrographical  range  are  likewise  present.  In  the 
closing  years  of  the  decade  of  the  eighties  discoveries  were 
made  of  silver-lead  ores  in  the  Carboniferous  limestones,  in  the 
neighborhood  of  intrusions  of  porphyry  and  sometimes  in  the 
contact  zones.  After  several  years  of  activity,  which  was 
maintained  despite  the  remoteness  from  rail,  the  low  price  of 
silver  caused  their  shutting  down.  The  Cumberland  mine,  the 
largest  opened,  formed  a  chimney  or  tubular  mass  in  the  lime- 
stone, and  was  proved  for  over  500  feet  in  depth.  Copper- 
bearing  veins  were  also  found  in  the  Belt  shales  of  the  Algon- 
kian in  the  northern  portion  of  the  area.^ 

In  the  extreme  northern  portion  of  Meagher  County,  and 
near  the  line  with  Cascade  County,  the  two  mining  districts  of 

'  R.  G.  Brown,  "Georgetown  Mining  District,"  Eng.  and  Mi n.  Jour., 
October  18,  1894,  345.  E.  G.  Spilsbury,  "Placer  Mining  in  Montana,' 
Ibid.,  Septembers,  1887,  p.  1G7. 

'  J.  E.  Clayton,  "The  Drumlummon  Group  of  Veins,"  etc.,  Eng.  ami 
Min.  Jour.,  August  4  and  11,  1888,  pp.  85,  10(5.  S.  F.  Einnions,  Tenth 
Census,  Vol.  XIII.,  p.  97.  L.  S.  Griswold,  "The  Geology  of  Helena,  Mont  . 
and  Vicinity,"  Jour,  of  the  Assoc.  Eng.  Soc,  XX.,  January  1898. 

'  Weed  and  Pir.sson.  "The  Castle  Mountain  District,  Montana,"  Bull. 
139,  U.  S.  Geol.  Survey,  1896. 


SILVER  AND  GOLD,   CONTINUED. 


821 


of  tb<' 

mines. 
(),  wero 
e  fouiul 
luntains 
n  many 
n  devpl- 
town  of 
ch  cany 
the  con- 
jnorphic 
Dikes  of 

tain  min- 
id  oreH  in 
al  section 
rusions  of 
e  flows  of 
t.     In  the 
Lries  were 
les,  in  the 
nes  in  the 

hicb   was 
price  of 

mint),  the 

1  the  lixne- 
Copper- 

he  Algon- 

)imty,  and 
istricts  of 

Min.  Jour., 
Montana, " 

.,  Eng.  and 
mous,  Tvnih 
lena,  Mont. , 
08. 
tana,"  Bull 


Neihart  and  Barker  are  located  in  the  Little  Belt  Mountains, 
but  their  outlets  are  to  the  north  at  Great  Falls.  At  Neihart 
there  is  a  series  of  fissure  veins  running  north  and  south,  in 
nietamorphic  gneisses  and  schists  which  are  cut  by  diorite. 
The  veins  are  narrow  and  barren  in  the  dark  colored  gneisses 
and  the  diorite,  but  carry  large  bodies  of  galena,  with  zinc- 
blende  and  pyrite  in  the  feldspathic  gneiss.  The  vein  filling 
is  replaced  and  altered  country  rock  with  quartz  seams  in  it. 
The  quartz  seams  in  some  mines  contain  much  polybasite, 
pyrargerite  and  chalcopyrite,  carrying  very  high  values  in  gold 
and  silver.  Dikes  and  larger  intrusions  of  quartz-porphyry 
also  occur,  but  are  unfavorable  to  the  veins,  as  in  them  the  lat- 
ter split  up  and  become  barren,  except  within  a  hujdred  feet  of 
the  surface.  At  Barker  the  ores  are  chiefly  silver- bearing 
galena  and  occur  along  the  contact  between  granite-porphyry 
and  limestone.' 

2.10.14.  Cascade  Countv  contains  important  coal  mines  and 
the  smelting  center  at  Great  Falls.  In  Missoula  County  at 
Quigley,  southeast  of  Missoula,there  is  auriferous  pyrite  in  slates 
of  Lower  Cambrian  or  Algonkian  age  "(W.  H.  Weed).  At 
Iron  Mountain  operations  were  formerly  carried  on,  but  are 
now  suspended,  and  there  are  various  minor  camps  throughout 
the  country.^ 

The  latter  statement  applies  as  well  to  Ravalli  County  in  the 
south.  Within  the  limits  of  the  Lewis  and  Clarke  Timber  Re- 
serve there  are  occasional  intrusions  of  porphyritic  rocks  in  the 
Algonkian  or  Lower  Cambrian  shales  and  limestones,  and  in 
the  neighborhood  of  the  igneous  rocks  copper  deposits  are 
found. ^  The  Reserve  lies  in  several  counties.  Similar  depos- 
its are  found  amid  the  high  peaks  of  the  Continental  Divide  on 
the  so-called  "Roof  of  the  Continent,"  along  the  line  of  Flat- 
head and  Teton  counties.* 

'  The  XX.  Atm.  Rep.  of  the  Director  of  the  U.  S.  Geol.  Survey,  which 
will  probably  be  issued  in  1901,  will  contain  a  paper  by  W.  H.  Weed,  on 
the  "  Mining  Districts  of  the  Little  Belt  IMountains. "  The  above  notes 
liave  been  kindly  furnished  bj'  Mr.  Weed,  in  advance  of  his  longer  jiaper. 

''  V.  D.  Smith,  "The  Cedar  Creek  Placers,"  Eng.  and  Min.  Join:,  Feb- 
niiivy  4,  1899,  143. 

^  K.  H.  Chapman,  "Geological  Structure  of  the  Rocky  Mountains  with- 
in the  Lewis  and  Clarke  Timber  Reserve."  Read  at  the  New  York  meet- 
ing, Amer.  Inst.  Min.  Eng.,  February,  1899. 

^  (1.  E.  Culver,  "  Notes  on  a  little  known  Region  in  Northwestern  Mon- 
taiiii  '  TniHs.  Wis.  Acad,  of  Science,  Arts  and  Letters,  VIII..  187,  1891. 


332 


KMMl'S  OliE  DEPOSITS. 


Ii| 


3.10.15.  In  Flathead  County,  in  the  extreme  northwestern 
corner  of  the  State,  on  Libbey  Creek  and  the  Yak  River,  there 
have  been  recently  diHcovered  large  deposits  of  gold-bearing 
pyrrhotite  in  diorite  similar  in  geological  relations  to  the  ores 
subsequently  described  at  Rossland,  B.  C.  Tellurides  were  re- 
ported some  years  ago  at  a  little  camp  called  Sylvanite. 

3.J0.  Ki.  Cboteau  and  Fergus  Counties.  Very  great  scien- 
tific interest  and  considerable  economic  importance  are  attached 
to  several  new  districts,  that  have  been  opened  up  in  the  small 
outlying  groups  of  mountains,  which  rise  from  the  plains  well 
to  the  east  of  the  main  chain  of  the  Rocky  Mountains.  They 
are  all  characterized  by  intrusions  of  igneous  rocks,  rich  in 
alkalies,  such  as  syenite- porphyries,  pbonolites,  and  related 
types.  These  are  the  rocks  which  are  present  in  the  Black 
Hills,  where,  in  the  Potsdam  sandstones,  tellurides  of  gold 
occur,  associated  with  fluorite;  and  at  Cripple  Creek,  Colo., 
where  the  ore  and  gangue  are  the  same.  Weed  and  Pirsson 
have  described  the  geology  of  the  Little  Rocky  Mountains. 
In  the  central  portion  of  a  roughly  elliptical  area  of  upheaval, 
crystalline  Archean  schists  are  seamed  by  intrusions  of  granite- 
porphyry,  syenite-porphyry,  and,  near  Landusky,  by  phouolite, 
Cambrian,  Siluro-Devonian,  Carboniferous  and  Jurassic  strata 
mantle  the  edges.  The  ore  and  gangue  are  found  coating  tlie 
fragments  of  decomposed  porphyry,  but  do  not  seem  to  lie  along 
well-defined  veins,'  The  parallelism  with  Cripple  Creek  is  close. 
The  Little  Rockies  are  situated  in  Choteau  County,  ISO  miles 
east  of  the  main  Rockies.  The  Judith  Mountains,  in  Fergus 
County,  nearer  the  central  part  of  the  State,  ai'e  larger,  but  of 
much  the  same  geological  structure.  A  core  of  syenite-por- 
phyry is  surrounded  by  the  sediments,  which  have  been  up- 
lifted by  its  intrusion  as  a  laccolite.  It  is  associated  with 
phonolite.  Where  the  igneous  rocks  cut  the  sedinientarics 
and  especially  along  their  contacts  with  a  white  Carboniferous 
limestone  free  gold   and  tellurides  with  associated  fiuorite  are 

'  W.  H.  Weed.  "Ore  Deposits  of  the  Little  Rocky  Mountains,"  £"//>/. 
and  Mi n.  Jour.,  May  2,  1896,433.  Weed  and  Pirsson.  "Geology  of  the 
Little  Rocky  Mountains,"  Jour,  of  Geo/.,  IV.,  399,  1891'..  See  also  E.S. 
Dana,  in  Col.  Wm.  Ludlow's  "Report  of  a  Reconnaissance  from  Carroll, 
Montana,  to  the  Yellowstone  National  Park,"  War  Dept.,  WashinKt""- 
1876,  137. 


SJLVEJi  AND  aOLD,   ('ONTINUKD. 


323 


western 
r,  thero 

bearing' 
bhe  ores 
were  re- 
nt acieii- 
attacbed 
he  Hinall 
una  well 
3.     They 
3,  ricb  in 
J  related 
:be  Black 
,  of   gold 
?k,  Colo., 
id  Pirsson 
[ouutains. 
upbeaval, 
)£  granite- 
pbouolite, 
asic  atrata 
oatiug  the 
0  lie  along 
ek  is  close. 
liSO  miles 
in  Fergus 
ger,  but  of 
yeuite-por- 
B  been  up- 
ated  witb 
inientaries 
rboniferons 
tluorite  are 


1 


tains,"  Enq. 
ology  of  the 
See  also  E.  S. 
from  Carroll, 
Washingi""- 


found  in  the  brecciated  limestone.'     Lewiston  and  Maiden  are 
the  chief  settlements. 

'i'lie  Sweet  Grass  Hills  near  the  Canadian  line  in  Choteau 
County  are  similar  in  geology  and  have  been  the  scene  of  some 
placer  mining.  Other  groups  of  mountain,  such  as  the  High 
wood  and  Bearpaw  ranges,  which  are  piles  of  volcanic  lavas 
and  tuffs,  are  known  to  contain  richly  alkaline,  igneous  rocks, 
but  ore  bodies  have  not  yet  been  reported." 

IDAHO. 

•2.10.17.  Ceo^ogr/y. —The  southern  part  of  the  State  extends 
into  the  alkaline  deserts  of  the  Great  Basin,  and  is  dry  and 
barren.  North  of  this  is  the  Snake  River  Valley,  which  is 
filled  by  a  great  flood  of  recent  basalt,  which  stretches  from  the 
Wyoming  line  nearly  across  the  State.  North  of  the  Snake 
River  a  large  area  of  granite  appears  in  the  western  portion, 
and  contains  many  mines.  Extensive  deposits  of  gravel  also 
occur.  Metamorphic  rocks  and  Paleozoic  strata  largely  consti- 
tute the  northern  portion  of  the  State,  and  are  penetrated  by 
many  igneous  intrusions.  The  eastern  part  lies  on  the  western 
slopes  of  the  Bitter  Root  Mountains,  whose  general  geology 
was  outlined  under  Montana.  The  geology  of  Idaho  has  been 
but  slightly  studied,  and  the  few  reliable  records  have 
resulted  from  the  scattered  itineraries  of  Hay  den's  survey,  iso- 
lated mining  reports,  and  the  collections  of  the  Tenth  Census,^ 

'  W.  i\I.  Courtis,  "Gold  in  Fossiliferous  Tiimestone  in  the  Judith  Jloun- 
taiiis,"  Ent].  and  Miit.  Jour.,  June  28,  1884,  478.  H.  C.  Freeniun,  'The 
Amnion  Mines,  Fergus  Co.,  Mont.,"  Idem,  Jlay  4,  189.5,  416.  W.  H.  Weed, 
"Mineral  Resources  of  the  Judith  Mines,"  Idem.  May  23,  18!)(),  496. 
Weed  and  Pirsson,  "  Geology  and  Mineral  Resources  of  the  Judith  Moun- 
tains." XVIII  Ann.  Rep.  U.  S.  Geol.  Surrey,  Part  III.,  p.  4i37. 

'  Weed  and  Pirsson,  "  Highwood  Mountains  of  Montana"/?///?.  Geol. 
Sor.  Amer.,Yl.,  389.  "Bearpaw  IMountain.s,"^wer.  Jonr.  ,SVj.,  May,  1H96, 
28:i  ;.Tune,  m\;  August,  136:  September,  188. 

■  (Jr.  F.  Becker,  Tenth  Censu.'i,  Vol.  XIII.,  53.  F.  H.  Bradley,  Hayden's 
Surrey,  19,72,  p.  208.  G.  H.  Fldredge,  "A  Geological  Reconnaissance 
across  Idaho,"  XVI  Ann.  Rep.  Dir.  U.  S.  Geol.  Surveij,  II.,  217.  F.  V. 
Harden,  Ann.  Rep.,  1871,  pp.  1,147;  1872,  p.  20.  W.  Lindgren,  "Mining 
Diistrictsof  the  Idaho  Basin  and  the  Boise  Ridge,  Idaho,"  XVTII  Rep.  Dir. 
U.  S.  Geo}.  Snn-ey,  Part  III.,  p.  617.  Pec.  Boise  Folio.  T.  S.  Geol.  Siinry. 
Rec.  Other  folios  are  in  preparation.  An  extended  pajxir  by  Lindgren 
is  in  press  for  the  XX.  Ann.  Report  of  the  U.  S.  Geol.  Survey,  which  will 


W^''~f 


3524 


jaJMJ'S  OHM  DEPOSITS. 


but  it  18  now  receiving  much  attention  from  tlie  U.  S.  Geologi- 
cal Survey. 

3.10.18.  The  extreme  northern  portion  of  Idaliohas  assumed 
increaning  interest  in  recent  years  on  account  of  the  notable 
mining  developments  in  the  neighboring  parts  of  British 
Columbia,  but  tliHCoveries  are  still  largely  in  the  nature  of 
prospects.  Kootenai  County  forms  the  so-called  "pan  han<''\" 
and  in  it  some  gold -quartz  veins  and  placers  are  known.  he 
great  silver-lead  mines  of  Coeur  d'Alene  in  Shoshone  County 
have  already  been  described  (:i.08.;*^).  Some  scattered  mining 
camps  occur  in  Talah,  Nez  Perces  and  Idaho  counties  to  tlie 
south.  In  the  extreme  southern  tongue  of  Idaho  County  is  tiu! 
Sheep  Mountain  district.  The  country  rock  is  granite,  with 
associated  schists  and  slates  in  larger  or  snui Her  masses,  often  as 
inclusions.  There  are  also  dikes  of  quartz-porphyrites  and 
diorite  porphyrites.  The  ores  are  impregnations  of  zones  of 
the  schists  or  slates,  with  silver-bearing  galena,  and  antimonial 
and  arsenical  sulphides.^ 

'I.IO.W).  In  Lendii  County  is  the  famous  old  gold  diggin{j;8 
at  Leesburg,  which  had  a  large  population  in  18")li-<J0,  l)iit 
which  are  now  practically  abandoned  except  for  an  extensive 
hydraulic  workings  at  California  Bar,  further  down  Napias 
Creek.  In  the  western  side  of  Lemhi  County  is  Yellow  Jacket, 
with  gold  ores  associated  with  a  complex  series  of  intruded 
igneous  rocks,  in  nietamorphic  schists."  The  ores  lie  along 
fractured  zones  and  in  the  Columbia  properties  are  chiefly  gold- 
bearing  chalcopyrite.  H.  H.  Armstead,  Jr.,  informs  the  writer 
that  tellurides  have  also  been  detected.  In  the  Yellow  Jacket 
mines  the  ore  is  free-milling  quartz.  In  northeastern  Lemhi 
County  is  Gibbonsville,  where  auriferous  pyrite  occurs  in 
quartz  veins  in  slates.'' 

2.10.20.  Custer  County  lies  south  of  Lemhi  and  contains 
several  well-known  mines.     The  Ramsliorn  is  in  metamorj)liic 

probably  be  issued  in  1901.    J.  S.  Newbeny,  "  Notes  ou  the  Geology  and 
Hotauy  along  tlie  Northern  Pacific  Railroad,"  Annah,  N.  Y.  Acad.  Sci., 
III.  252.     Raymond's  R('jH>rts  on  Mhicriil  licsourccf;  West  of  the  Ruckij 
Mountains.     O.  St.  John,  Haijden's  Sunry.  1877,  p.  82J;  1878,  p.  175. 
'  G.  H.  Eldredge,  XVI.  Ann.  Rep.  U.  S.  Geol.  Survey.     Part  II.,  p.  258 
^  G.  H.  Eldi-idge.    "A  Geological  Reconnaissance  Across  Idaho,"  XVI 
Ann.  Rep.  U.  S.  Geol.  Survey,     II.,  259. 
=  B.  MacDonald.  Eng.  and  Min.  Jour.,  October  3,  189C,  3i9. 


I'm.  I'^i). — Tlic  old  (jnld  ilififiiiH/s  on  .Xiijiids  Crcfk.  Lcrshitiy,  lihtlio,  illiiH 

tnifiiKj  (III  iilxniiloihil  iiliiri'i'  (•diiij).      Fiom  it 

lilittltii/riiiih  1)1/  J.  /•'.   Ki  iiiji.  islHi. 


Fig.  I'iQ.  —  Vicii'  on  Xiipias  Circk.  bcloiv  California  Bar,  Idaho,  after  a 
freshet.  From  a  jihotograjili  by  J.  F.  Kemp,  1 «!)('). 


SILVER  AND  GOLD,   CONTINUED. 


325 


slates  on  a  fissure  vein  thai  has  rich  chutes  of  high-grade  sil- 
ver ores  in  a  siderite  gangue.  The  Custer  and  the  Charles 
Dickens  are  farther  west,  near  Bonanza  City,  and  afford  both 
silver  and  gold  in  quartz  gangue  from  veins  in  porphyrj'. 
Smelting  ores  occur  in  the  region,  and  have  been  used  in  some 
operations  based  on  this  treatment.  Boise  and  Elmore  coun- 
ties, on  the  west  and  southwest  of  Custer,  contain  very  impor- 
tant mining  districts.  Lindgren  has  shown  the  extensive  de- 
velopment of  a  gray,  rather  basic  granite,  having  close  affini- 
ties with  the  quartz-mica-diorites.  It  is  penetrated  by  numer- 
ous dikes  of  porphyries  and  minettes  and  is  covered  by  Tertiary 
lake  beds  and  effusive  rocks.  The  granite  has  suflFered  consid- 
erable faulting,  usually  on  a  small  scale,  and  in  a  number  of 
districts  the  fissures  thus  formed  have  been  the  scene  of  ore  de- 
position. Their  general  characters  are  shown  bj'"  Fig.  r27. 
They  may  occur  as  single  and  isolated  fissures,  as  parallel 
series,  or  as  lines  of  crushing  with  disjointed  vein  fillings. 
Quartz  is  the  almost  invariable  gangue,  calcite  being  very 
subordinate.  The  metallic  minerals  arepyrite,  gold,  arsenopy- 
fite.  zincblende  and  galena.  These  sulphides  likewise  impreg- 
nate the  wall  rock,  but  they  are  then  low  in  the  precious  metals. 
Silver  is  invariably  present,  and  in  the  Banuer  district  in  Elmore 
County,  it  is  the  chief  source  of  value.  At  Atlanta,  likewise  in 
Elmore  County,  the  lode  is  of  quite  extraordinary  size,  being 
known  for  two  and  one-half  miles,  with  an  average  width  of  sev- 
euty-five  feet,  and  with  many  spurs.  The  pay  ore  occurs  in  four 
or  five  shoots  in  the  main  vein,  which  are  of  moderate  widths. 
Silver  predominates  over  '^old.  In  the  neighborhood  of  the  gold- 
bearing  veins  in  granite,  placers  have  been  and  are  extensively 
operated,  and  indeed,  led  to  the  settlement  of  the  country.  The 
principal  deep-mining  localities  are  the  Idaho  City  belt,  the 
Quartzburg-Grimes  Pass  belt,  both  v/ithin  the  de{)ression  known 
as  the  Idaho  Basin :  and  then  in  the  mountains  to  the  west, 
called  the  Boise  ridge,  there  are  the  Neal,  Black  Hornet,  Boise, 
Shaw  Mountain,  Willow  Creek  and  Rock  Creek  districts.' 

'  J.  E.  Clayton,  "Atlanta  District,"  Traits.  Aiiicr.  Inst.  Min.  Eikj., 
VI,,  -lOS.  G.  H.  Eldridge,  "  A  Geological  Reconnaisstiuce  Across  Idaho," 
A'TT.  Aint.  R(p.  U.  S.  Gcol  Snnrif.  21T.  W.  I.indgren,  "  Mining  nistricts 
(if  t lie  Idalio  Basin  and  the  Boise  Kidge,  Idaho,"  XVIIl,  Idem,  Part  111.. 
P  t!l7.  Rec.  The  Boi.se  Folio,  U.  S.  Gcol.  Survey.  Rec.  An  iinfKjrtant 
IiaixT  may  he  expected  m  the  A'A'.  Ann.  Rep.  of  the  Survey. 


I?  ■ 


326 


KEMP'S  ORE  DEPOSITS. 


/'v^■?i;'^i'';;-•■;':>;^;■!^■^i■;•':;';/ " '' 


Mmm 


••/■■■.'  ■ 


■'/•"■^•''•^l''^'''r^'-''-'^''^-^'i^''V:'' 


10  ftel 


6 


'^'•■^'■'^■■''^■' 


Fig. 


137. — Sections  to  illustrate  typical  gold  veins  in  the  Boise  granite  region, 
Tdaho.     After  W.  Lindgren,  XVIIL  Ann.  Hep.  U.  S.  Oeol. 
Survey,  Part  III.,  Plate  XV. 


Sii;. 


1.  Simple  Assure  vein  on  one  fault  plane,  witli  quartz  filling,  wliich  alone  is  ore.  Wallmck 
altered,  but  barren.  U.  Complex  Assure  with  four  fault  planes.  Rich  ore  Alls  the  lonj;  nar- 
row openings  and  impregnates  adjacent,  altered  widl-roek.  3.  Simple,  narrow,  fissure  vein, 
Ailed  with  ore  which  also  impregnates  altered  wall-rock.  4.  Comple.\  Assure  vein,  willi  twn 
fault  planes.  Intermediate  rock  and  outer  walls  altered,  the  former  also  sheeted.  .I.  Irnm 
larly  shattered  zone  l)etweeu  two  fault  planes.  Intermediate  rock  excessively  altrrcil. 
Quartz  Alls  seams  and  cracks.  0.  Quartz  vein  of  rich  ore  along  under  side  of  nltiivil 
porphyry  dike  and  with  branches  into  hanging.    Altered  dike  forms  low-grade  ore. 


is  ore.  WaUiock 
liUs  the  louc  "!"■- 
i-ow,  Hssure  vein, 

iiv  vein,  Willi 'W'^ 
i-eted.  r,.  Irnrii- 
cessively  ult'i'"'- 
.,•  side  of  nil  >■>••''» 
■raUe  ore. 


SILVER  AND  GOLD,   CONTINUED. 


327 


2.10.21.  Alturas  County  contains  one  very  important  silver- 
lead  district,  tlie  Wood  River,  which  has  been  earlier  referred 
to  (under  Example  32a).  Owyhee  County  forms  the  southwest- 
ern corner  of  the  State.  Apparently  the  same  granite  that  is 
so  prominent  in  Boise  and  Elmore  reappears  from  beneath  the 
intervening  Tertiary  deposits,  and  comes  up  near  Silver  City. 
Still  further  southwest  quartz- porphyry  and  metamorphic  rocks 
are  found  with  dikes  of  basalt.  Gold-quartz  and  high-grade  sil- 
ver ores  are  present.  The  Poorman  Lode  is  famous  for  ruby 
siilver  ores.  W.  P.  Blake  mentions  seeing  a  piece  from  this 
mine  at  the  Paris  Exposition  which  weighed  about  200  pounds.^ 
It  was  awarded  a  gold  medal.  The  crystal  from  which  it  was 
broken  weighed  500  pounds.^  In  Cassia,  Logan,  Oneida  and 
other  counties  in  the  southern  part,  placers  are  being  or 
have  been  worked,  and  in  Bear  Lake  County,  in  the  southeast 
corner,  salt  and  sulphur  deposits  are  recorded.'  The  gold  of 
the  Snake  River  sands  is  extremely  fine,  and  difficult  to  save. 

'  Avu'v.  Jour.  ScL,  ii.,  XLV.,  97. 

'  Raymond's  Rejyorts  on  ilineml  Resources  West  of  the  Rocky  Mountains, 
1.^(58,  p.  523. 

=  G.  F.  Becker.  Tenth  Census,  Vol.  XIII.,  p.  59.  T.  Egleston,  "The 
Treatment  of  Fine  Gold  in  tlie  Sands  of  the  Snake  River,  Idaho,"  Trans. 
Aiiicr.  Inst.  Min.  Eng.,  XYllI.,  Tidl.  Raymond's  Reports  on  Mineral  Re- 
sources West  of  the  Rocky  Mountains.    Rep.  Dir.  of  the  Mint,  1883,  p.  227. 


^1. 


jranite  region, 
Geol. 


wr 


V-     ! 


CHAPTER  XI. 

SILVER  AND  GOLD,    CONTINUED.— THE  REGION  OF  THE  GREAT 
BASIN,   IN  UTAH,    ARIZONA,    AND  NEVADA. 

UTAH. 

2.11.01.  Geology.— The  eastern  half  of  Utah,  terminating 
with  the  western  front  of  the  Wasatch,  is  in  the  Colorado 
Plateau,  but  the  western  is  wi<'  in  the  limits  of  the  Great 
Basin.  The  plateau  portion  consists  largely  of  Mesozoic  strata, 
quite  horizontal  and  more  or  less  carved  by  erosion.  The  east 
and  west  arch  of  the  Uintah  Mountains,  in  the  northern  part, 
has  upheaved  them,  so  that  where  the  Green  River  has  out  a 
channel  across,  the  Paleozoic  is  exposed  in  great  strength.  The 
Wasatch  range  rises  with  a  gradual  ascent  from  the  east,  and 
then  terminates  with  a  great  fault  line,  having  a  steep  westerly 
front.  This  line  of  weakness  was  developed  in  the  Archean 
and  has  been  a  scene  of  movement  even  to  recent  times.  It  is 
a  very  important  structural  feature.  West  of  the  Wasatcb, 
which  is  a  fine  example  of  block-tilting  in  mountain-making, 
the  mountains  belong  to  the  Basin  ranges,  which  are  more  typ- 
ically developed  in  Nevada.  The  Wasatch  section  was  shown 
by  the  Fortieth  Parallel  Survey  to  involve  1:^,000  to  14,()(io 
feet  of  the  Upper  Archean,  and  nearly  30,000  feet  of  the  Pale- 
ozoic. In  southern  Utah  the  Tria£:3ic  rocks  are  important  and 
contain  some  rich  mines. ^ 


'  G.  F.  Beoker,  Tenth  Cemns.  XIII.,  38.  Wliitman  Cross,  "The  Lacfo- 
litic  Mountain  Groups  of  Colorado,  Utah  and  Arizona,"  XIV.  Ann.  Rep. 
U.  S.  GeoL  Siirvcij,  Part  II.,  165.  C.  E.  Dutton,  Report  on  the  High  Pla- 
teaus of  Utah,  Washington,  1H80.  S.  F.  Eninioiis,  "Origin  of  Green 
River,''  Science,  VI.,  Id,  1807.  Sir.  A.  Geikie, "  Archean  Rocks  of  tlie  Wa- 
satcli  Moimtains,"  Anier.  Jour.  Sci.,  iii.,  XIX.,;{(iiJ.  G.  K.  Gilhert,  "Lake 
Bonneville,  "  Monograph  I.,  U.  S.  Oeol.  Survey,  and  II.  Ann.  Rep.,  160-'2()(). 


[E  GREAT 


SILVEIi  AND  GOLD,   CONTINUED. 


320 


2.11.0'^.  The  greater  number  of  the  Utah  mines  are  fo'  lead- 
silver  ores,  and  have  been  mentioned  under  "Lead- 
silver."  The  north v^^eatern  county.  Box  Elder,  is  in  the  alka- 
line desert  region  of  the  Great  Basin.  The  mining  districts 
occur  in  the  central  part  of  the  State,  in  the  Wasatch  and 
Oquirrh  mountains,  md  are  also  found  in  the  extreme  south- 
west. 

2.11.03.  Ontario  Mine.  Nearly  east  of  Salt  Lake  City,  in 
Summit  County,  is  the  Ontario  mine,  a  vein  from  four  to 
twenty -three  feet  wide  (averaging  eight  feet),  in  quartzite,  but 
extremely  persistent,  being  opened  continuously  for  0.000  feet. 
In  the  lower  working  a  porphyry  dike  has  come  in  as  one  of 
the  walls.  It  is  extensively  altered  by  fumarole  action  to  clay. 
The  best  parts  of  the  mine  have  quartzite  walls.  The  ores 
consist  of  galena,  gray  copper,  silver  glance,  blende,  etc. 
The  Ontario  vein  extends  through  a  number  of  claims  and  at 
least  one  other  important  vein  is  known,  the  Daly  West,  which 
however,  has  one  wall,  limestone.  Its  product  and  the  latter 
developments  on  the  Ontario  have  changed  the  camp  to  a  lead- 
silver  producer.^ 

2.11.04.  The  lead-silver  veins  of  Bingham  Canon,  in  Salt 
Lake  County,   have  already  been  mentioned.     Reference  may 

•The  Ancient  Outlet  of  tlie  Great  Salt  Lake,"  Amer.  Jour.  ScL,  iii.,  XV., 
^->(i;  XTX.,  341;  .see  also  A.  C.  Peale,  Ibid.,  XV.,  439.  "The  Henry 
^lomitains,"  Washington,  1877.  R.  C.  Hills,  "  Tyjies  of  Past  Eruptions  in 
I  he  Rocky  Mountains,"  Proc.  Colo.  Sci.  Soc,  IV.,  14.  International  Geo- 
Idsioal  Congress,  Wasiiington  meeting,  1891,  Guide  Book  to  the  Rocky 
Mountains.  J.  D.  Irving,  "The  Stratigraphical  Relations  of  the  Browns' 
I'ark  Beds,  Utah,"  Trans.  N.  Y.  Acad.  Sci.,  XV.,  252.  Hague,  Kinj,',  and 
Eiimions,  Fortieth  Parallel  Siwvey,  Vols.  I.  and  II.  0.  C.  Marsli,  "  On  the 
Geology  of  the  Eastern  Uintah  Mountains,"  Amer.  Jour.  Sci.,  iii.,  I.,  101. 
IT.  ]\lontgonierv.  "Volcanic  Dust  in  Utah  and  Colorado,"  Science,  I.,  (;.")(>, 
lN!)"i.  B.  Sillinian,  "  Geological  and  Mineralogical  Notes  on  Some  of  the 
I^Iining  Districts  of  Utah  Territory,"  ^?He>\  Jour.  Sci.,  iii.,  III.,  195.  G. 
O.  Smith,  "  Igneous  Phenomena  in  the  Tintic  Mountains,  Utah,"  Science, 
VII..  M)2.  1898.  J.  Walther,  "The  North  American  Deserts,"  iV«i.  Gcog. 
MiKjazinc,  IV.,  I(i3.  Wheeler,  Gilhert,  Lock  wood  and  others,  on  We.stern 
Utah,  Wheeler's  Sneveij,  Rep.  Prog..  1869-71-72.  Idem.  Final  Reports,  III. 
'  T.  J.  Almy,  "  Hi.story  of  the  Ontario  Mine,  Park  City,  Utali,  '  Trans. 
Amer.  Inst.  Min.  Eng.,  XVI.,  'ij.  "The  Ontario  Mine,"  Eng.  and  Mm. 
Jour.,  :\Iay  28,  1881,  p.  36.5.  D.  B.  Huntley,  Tenth  Census,  Vol.  XIII.,  p. 
4:i8.  H.  L.  J.  Warren.  "The  Daly  West  Mine,  Park  City,  Utah,"  Eng. 
ami  Min.  .lour.,  October,  14,  1899. 


•ii! 


«i 


330 


KEMP'S  ORE  DEPOSITS. 


again  be  made  to  the  great  bed- veins  of  gold  quartz  associatt^nl 
with  them.  Ophir  Canon  and  Dry  Canon,  in  Tooele  County, 
and  the  Tintic  district,  in  Juab  County,  have  also  been  de- 
scribed. In  addition  to  the  smelting  ores,  others  have  been 
treated  by  milling.  Quite  recently  interest  has  been  directed 
to  the  mines  of  the  Camp  Floyd  district,  of  which  Mercur  is 
the  chief  town.  Rich  deposits  of  gold  ores,  formerly  refrac- 
tory, have  yielded  to  the  cyanide  process,  and  have  given  a 
newandlargj  lease  of  lite  to  a  district  that  was  abandoned 
years  ago,  after  having  had  a  short  career  as  a  silver  producer. 
Mercur  is  situated  in  the  southern  end  of  the  Oquirrh  Moun- 
tains, in  a  valley  known  as  Lewiston  Canon.  A  thick  series 
of  Carboniferous  limestones  and  very  subordinate  shales  lias 


8.M  SO  W. 


SELIION  E-E. 

Fig.  128. — Geolof/icnl  croHHKections  at  Mercur,  Utah,  reduced  from  colored  ones 

by  J.  K.  Spurr;  XVI.  Ann.  Rep.  Dir.  U.  S.  Oeol.  Survey,  Plate 

XX  VII.     The  sections  cut  each  other  at  right  angles. 

been  folded  into  a  low  anticline,  as  shown  in  Fig.  128,  whose 
axial  crest  is  also  folded ,  so  that  the  beds  constitute  a  low  dome 
or  swell.  One  great  stratum  of  limestone  has  been  intruded 
by  an  interstratified  sheet  of  quartz  porphyry,  locally  called 
the  Eagle  Hill  porphyry,  which  at  the  most  productive  miues 
has  split  into  three  thin  sheets,  each  150  feet  or  less  from  its 
neighbor.  At  some  time  after  the  intrusion,  ore-bearing  circu- 
Iftions  percolated  along  the  lowest  sheet  and  impregnated  the 
limestone  for  a  zone,  usually  10  to  20  feet  thick,  but  reaching 
even  r»0  feet  or  more,  with  silver-bearing  minerals  in  a  gaugne 
of  cherty  quartz.  Where  mined  the  silver  was  present  in  tliiii 
films  of  the  chloride  coating  fragments  of  the  chert  and  lime- 


SILVER  AND  GOLD,   CONTINUED. 


331 


stone.  Associated  metallic  minerals  are  few.  Stibnite  is 
known,  and  pyrite  has  been  detected  with  the  microscope.  Car- 
bonates of  copper  have  been  noted.     As  gangue  minerals  cal- 


bhaibi) 


libabbb 

EEII3         \Zimi        Er3 

QCABTZ-rOKniYRY  ORE  FUESU  LIMESTONE 

(Altered)  (Allercd  limcstoag) 

Fig.  i2d.— Diagram  showing  rclutio/i .10/ ore  to  fdiiU  in  Tunnel  No.  3,  Marion 
Mine,  Mercur,  Utah.     Scale  40  feet  to  the  inch.     After  J.  E.  8purr, 
XVL  Ann.  Hep.  U.  S.  Geol.  Survey,  430. 
swr. 


J  J.'  :.  '""^^rr '  '.j\  Jj         '   "      ..     \T  L 


Mouth  of 
Tunnel 


QUARTZ-PORPHYRT 
(Altered ) 


ORE 

(AUcre'l  limrstone, 

containing  boffldcrs 

of  ilccunipositloD.) 


E3^ 

FRESH  LIMESTONE 


Fig.  130. — Section  along  the  (ieyner  mine  tunnel,  Mercur,  Utah.    After  J.  E. 
Spurr,  XVI.  Ann.  Rep.  U.  S.  Geol.  Survey,  422. 

cite  and  barite  are  next  to  chert  in  abundance.  Spurr  favors 
heated  waters  as  the  vehicles  of  the  ore.  Long  after  the  silver 
ores  had  been  deposited  the  gold  series  were  formed,  pi'obably 
as  tellurides,  along  the  contact  of  the  next  overlying  sheet  of 


*«;! 


i^:^ 


332 


KEMP'S  Olt/'J  DEPOSITS. 


porphyry.  They  are  now  t'ouud  where  this  sheet  is  cut  by  a 
series  of  small  northeast  fissures  in  the  limestone,  which  fis- 
sures are  thought  with  great  reason  by  Spurr  to  have  been  the 
conduits  through  which  the  ores  were  introduced.  The  gold  in 
the  oxidized  ores  is  in  some  condition  that  is  readily  soluble  in 
potassium  cyanide,  but  it  is  uncertain  what  that  state  is.  Re- 
algar and  occasionally  cinnabar  are  associated  with  it.  In  the 
unoxidized  ores  pyrites  are  abundant,  bo:  the  gold  is  but 
slightly  attacked  by  the  cyanide.  It  is  thought  to  have  been 
deposited  as  a  telluride.  The  ores  average  about  ten  dollars 
per  ton.  The  region  is  poorly  supplied  with  water,  and  all  tlie 
springs  are  carefully  utilized.  R.  C.  Hills,'  in  the  paper  cited 
below,  explained  the  ores  as  introduced  through  a  series  of  fis- 
sures which,  now  filled  with  calcite,  penetrate  to  the  chutes. 
J.  E.  Spurr,"  however,  regards  the  open  fissures  along  which  the 
chutes  extend,  as  the  conduits,  and  favors  a  vaporous  or  funia- 
rolic  method  of  introduction,  A  laccolite  of  igneous  rock  at 
some  uuknown  point  below  is  suggested  as  the  source  of  ttie 
vapors.^ 

Considerable  interest  has  been  directed  of  late  to  the  mines  of 
the  Deep  Creek  district,  on  the  extreme  western  border  of  Utah, 
in  the  Ibapah  range.  Limestones  regarded  by  Blake  as  Car- 
boniferous, and  other  sedimentary  rocks,  have  been  broken 
through  by  great  outflows  of  granite,  andesite,  hyperstbene-an- 
desite,  etc.  The  ore  bodies  appear  to  ba  contact  deposits  in 
limestone  near  igneous  recks,  and  carry  much  free  gold.* 

•  R.  C.  Hills,  "  Ore  Deijosits  of  Camp  Floyd  District,  Tooele  Co.,  Utali," 
Pi'oc.  Colo.  Sci.  Soc,  August  (!,  1S04.     Rec. 

^  J.  C  Spurr,  "Econouiic  Geology  of  tlieMevcur  Mining  District,  Utali,  " 
with  an  Introduction  by  S.  F.  Emmons.  XV f.  Ann.  Rep.  Dir.U.  S.  Geo!. 
Snririf.  II.,  349.     Re". 

^  Otlier  ])apers  on  Mercur  are  the  following:  R.  C.  Gemniell,  "  Tlie 
Camp  Floyd  Mining  District  and  the  Mercur  I\Iine,  Utah,"  Eng.  and  Mm. 
Joiir.,  LXIII.,  40;?,  1897.  A.  Lakes,  "The  0(piirrii  Mountains  or  the  M(m- 
cur  Mining  District.  Utah,"  Colliery  Engineer,  XVI.,  24:5.  ^S9(J.  W.  IT. 
Moeller,  "  Tiie  Mercur  Gold  Deposit  in  the  Camp  Floyd  District,  Utah," 
Eng.  and  Min.  Jonr.,  LVII.,  51,  1894.  D.  Maguire,  "Gold  Mines  of 
Mercur,"  ilZ/xcs  and  Minerah.  XIX.,  81,  130,  1S98.  J.  W.  Neill,  "Camp 
Floyd  Di.strict,  Utah,"  Eng.  and  Min.  Jonr..  LXI.,  8."),  189('). 

*  W.  P.  Blake,  "  Age  of  the  Limestone  Sti'ata  at  Deep  Creek,  Utah,  and 
the  Occurrence  of  Gold, "etc..  Anier  Geol ,  January,  18!>'3,  p.  47.  Eng.  and 
Min.    Jour.,  February  23,  1892,  p.  253.      S.  F.  Emmons,  Fortieth  Parallel 


B' 


iiit  by  a 
lich  fis- 
jeen  the 
gold  in 
luble  in 
is.     Re- 
in the 
I  is  but 
we  been 
3  dollars 
d  all  the 
per  cited 
,es  of  tis- 
e  chutes. 
,'hich  the 
or  f  uma- 
is  rock  at 
•ce  of  ttie 

mines  of 
of  Utah, 
e  as  Car- 
broken 
lene-an- 
aposits  in 
Id.* 

:;o.,  utaii, " 

ict,  Utah," 
U.  S.  Geol 

i(>ll,  "Tin- 
(ind  Mm. 
n-  the  Mer- 
le. W.  II. 
ict.  Utah." 
Mines  of 
11,   "Camp 

Utah,  and 

th  ParaUd 


Fi(i.  lol. — Opcnetit.  slimriiKj  tlic  ixii/strcdh;  at  Mcrcnr,  Utah.     From  a 
2>hoto(jrtiplt  hi/  /'.  K.  IlHihoii.  1S!)8. 


Fig.  132.— riie  Golden  Gate  eijanide  mill.  Mereitr  disfriet,  Utali.     From 
a  photoiiraph  by  L.  E.  Riter,  Jr.,  1H98. 


SILVER  AND  (iOIJ),  CONTINUED. 


333 


In  Beaver  County  the  interesting  depoHitH  of  the  Horn  Sil- 
ver, the  Carbonate,  and  the  Cave  ore  bodies  liave  been  men- 
tioned under  Examples  W(j,  '.y.\a,  and  '.)'ih.  The  iron  ore 
liddies  of  Iron  County  will  be  found  under  Example  14.  In 
Piute  County,  near  the  town  of  MaryHvalo,  around  Mount 
Biildy,  are  a  number  of  mines  with  lead-silver  or  niillinj^  ores 
in  quartz  porphyry  (copper  belt),  or  between  limestone  and 
([uartzite  (Deer  Trail,  Oreen-eyed  Monster,  etc.).  Selenide  of 
mercury  is  found  in  the  Lucky  Boy.' 

2.11.05.  Example  41.  Silver  Reef,  Utah.  Native  silver, 
cerarji;erite  and  argentite,  impregnating  Triassic  sandstones, 
and  often  replacing  organic  remains.  These  deposits  were 
earlier  referred  to  under  Example  21,  p.  80.  They  were  dis- 
covered in  1877.  At  Silver  Reef  there  are  two  silver-bearing 
strata  or  reefs,  with  beds  of  shale  between.     Above  the  water- 


Runs  into_ 
barren  rook 


Fig.  133. — Two  sections  of  the  argentiferous  sandstone  of  Silver  Reef,  Utah. 
After  0.  M.  Rolker,  Trans.  Avier.  Inst.  Miii.  Eng.,  IX  ,  p.  31. 


line  the  ore  is  horn  silver;  below  it  is  argentite.  At  times  it 
replaces  plant  remains;  f»t  other  times  no  vis^ible  jiresence  of 
ore  can  be  noted,  although  the  rock  maj'  afford  ^oO  to  the  ton. 
The  silver  always  occurs  along  certain  ore  channels,  distributed 
tlirough  parts  of  the  sandstone.  The  origin  of  the  deposits 
has  given  occasion  to  a  vigorous  discussion.  J.  S.  Newberry 
held  that  the  silver  was  deposited  in  and  with  the  sandstone 
from  the  Triassic  sea,  although  it  may  have  been  concentrated 
since  in  the  ore  channels.  P.  M.  F.  Caziu  holds  that  the  or- 
ganic remains  were  deposited  in  and  with  the  sandstone,  and 
that  these  were  the  immediate  precipitating  agents  of  the  ores. 
R.  P.  Rothwell  explained  them   much  as  does  Rolker,  below. 


tinmey.  Vol.  II.,  p.  475.     J.  F.  Kemp,  "  Petrogniphical  Note.s  on  a  Suite  of 

Uocks  Collected  by  E.  E.  Olcott,"  Trans.  N.  Y.  Acad.  ScL,  XL,  137,  1892. 

'  G.  J.  Brush,  "  On  the  Ouofiite,"  etc,  Amer.  Jour.  Sci.,  iii.,  XXI.,  312. 


'Mft 


384 


KKMrs  OliH  DEPOSITS. 


11 


C.  M.  Rulkor,  who  vvaa  for  some  years  in  charge  of  He  vera  1  of  the 
niines  has  also  written  about  them,  aud  in  prohahly  nearest  to  the 
truth.  Rolkeravgues  that  the  impregnation  was  subsequent  to 
the  formation  of  tiio  sandstone,  and  was  caused  by  tiie  igneous 
outbreaks  in  tboneighboriiood,  and  probably  runs  along  old  lines 
of  partial  weakening  or  crushing  that  afterward  healed  up. 
Eruptive  rocks  are  known  in  the  neighborhood  of  the  ores  both 
in  Utah  aud  in  the  Nacomiento  copper  district  of  New  Mexico. 
From  what  we  know  of  ore  deposits  in  general  this  seems  most 
probable,' 

ARIZONA. 
2.11.00.  Gcohnfj/. — Arizona  lies  ])artly  in  the  plateau  re- 
gion, and  partly  in  the  Great  Basin.  Tlie  Basin  ranges  con- 
verge with  the  Kocky  Mountains,  which,  however,  are  chietiy 
in  New  Mexico.  Tlie  uplands  of  the  ranges  are  well  watered 
and  covered  with  timber,  but  the  low-lying  portion  of  the 
Great  Basin  is  an  arid  desert,  and  in  southwestern  Arizona  is 
the  hottest  part  of  the  United  States.  Cretaceous  and  Jura- 
Trias  largely  form  the  plateau  region.  Running  southeast  to 
northwest  is  the  great  development  of  Carboniferous  limestone 
so  often  referred  to  under  "Copper,"  and  underlying  this  are 
found  Archean  granites,  gneisses,  etc,  A  great  series  of  ore 
deposits  is  ranged  along  this  contact.  In  the  southwest  are 
mountai'^8  of  granites  and  metamorphic  rocks.  The  Territory 
also  contains  vast  Hows  of  igneous  rocks,  and  in  the  plateau 
country  between  the  converging  ranges  some  ;i(»,0(iU  or  ::ir),»i(i(» 
square  miles  are  covered  by  them.  The  Grand  Caiion  of  the 
Colorado  has  laid  bare  a  magnificent  geological  section  of 
many  thousand  feet,  from  the  Archean  to  the  Tertiary.'^ 

'  F.  M.  F.  Cazin,  "The  Origin  of  *!\e Copper  and  Silver  Ores  in  Triassic 
Sanflrock,"  Em/,  and  Miii.  Jour.,  Decunherll,  IHSO,  ]).  :]M1 ;  April  ;W,  18.SI, 
p.  :>()0.  "The  Silver  Sandstone  Fonnation  of  Silver  Reef,"  H>iif.,  May  2'i, 
IHSO,  p.  351;  January  10,  IT,  34,  1880,  pp.  25,  48,  79  (Kothwell).  A.  W 
.Jackson,  "Silver  in  Sedimentary  Sandstone,"  7?('^).  Dii:  of  Mint,  IHH'i,  ]> 
3H4,  reprinted  from  Cal.  Aiual.  Svi.  J.  S.  Newberry,  "Report  on  llic 
Properties  of  the  Storniont  Silver  Mining  Company,"  etc.,  Eiig.  and  Miii. 
.Jour.,  October  23,  1880,  p.  2(i9.  "The  Silver  Reef  Mines,"  Ibid.  January 
1,  1881,  p.  4.  C.  M.  Polker,  "The  Silver  Sandstone  District  of  Utah." 
Tram.  Amer.  Inst.  Min.  Eng.,  IX.,  31. 

»  "Central  Arizona,"  Eng.  and  Min.  Jour.,  April  23,  1881,  p.  285.     "  Col 
omdo  River  of  the  West,"  review  of  Ives  Expedition,  Amer.  Jour.  Sci.,  ii. 


m 


8ILVKH  AND  aOLD,   CONTJMh'JJ. 


885 


'i.  11.07.  Apache  County  is  in  the  northejisteru  corner.  In 
the  southern  \mvi  of  tlie  county  gold  and  wilver  ores,  in  veins  in 
linu'stone,  associated  with  copper  ores,  are  reported,  and  some 
sniiill  [ilaeers. 

:.M1.()H.  Yavapai  County.  Gold  and  silvei"  ores,  in  (juartz 
veins,  in  granite  and  nietaniorphic  rocks.  The  Black  range 
copptT  district  has  already  been  referred  to  under  Example  2Uc. 

Mohave  County.  Silver  sulphides,  arsenides,  etc.,  and  alter- 
ation products  in  veins  in  granite,  at  times  showing  a  gneissoid 
Btiucture.     Only  the  richest  can  now  he  worked. 

^'uma  County.  Quartz  veins,  with  silver  ores  and  lead  min- 
erals in  metamorphosed  rocks  (gneiss,  slate,  etc.),  or  in  gran- 
ite. 

Maricopa  County  contains  both  Paleozoic  and  Archean  ex- 
posures. The  ore  deposits  lie  mostly  along  the  contact  of  the 
two,  in  granite  or  highly  metamorphosed  strata.  They  are 
usually  (juartz  veins,  with  silver  ores  and  copper,  lead,  and 
zinc  minerfils.  The  Globe  district,  extending  into  Pinal 
County,  is  the  principal  one.  Mention  has  already  been  made 
of  it  under  "Copper,"  Example  '^Oc. 

Pinal  County  adjoins  Maricopa  on  the  south  and  contains  a 
iininber  of  important  mines.  They  produce  mostly  silver  ores, 
with  lead  and  copper  associates,  and  some  blende.  The  gaugue 
minerals  are  (juartz,  calcite,  etc.,  occasionally  manganese  com- 
pounds, and  sometimes,  in  the  granites,  barite.  Limestone,  slate, 
sandstone,  and  (juartzite,  as  well  as  granite,  diabase  and  diorite, 
occur  as  wall  rock. 

'11.00.  Silver  King  Mine.  A  central  mass  or  chimney  of 
quartz,  with  innumerable  radiating  veinlets  of  the  same,  carry- 
ing rich  silver  ores  and  native  silver,  in  a  great  dike  of  feld- 

XXXIII.,  387.  G.  F.  Becker.  Tenth  Cemns,  Vol.  XIII.,  i>.  44.  C.  E.  Diit- 
ton,  "The  Pliysical  Geology  of  the  Grand  Cafion  District,"  ab-stract  of 
Mitiiofjniph  II.,  Sec.  Ann.  Hep.  Dir.  U.  S.  Geol.  Survey,  49-101 ;  see  also  the 
^Idiiograph.  P.-itrick  Hamilton,  The  ResoHrce,<i  of  Arizona.  A.  L.  Bancroft 
I'e  Co.,  San  Francisco,  1884.  B.  Silliinan,  "Report  on  Mining  District.s  of 
Arizona,  near  the  Rio  Colorado,"  Eng.  and  Min.  Jour.,  August  11,  1877,  p. 
Ill;  taken  from  Amer.  Jour.  ScL,  ii.,  XLL,  3Hi).  C.  D.  Wolcott,  "Permian 
nnd  Otlier  Paleozoic  Groups  of  the  Kanab  Valley,  Arizona,"  Amcr.  Jour. 
Sfi.,  iii.,  XX.,  221.  "  Pre-Carboniferous  Strata  in  the  Grand  Cafion  of  the 
<  (ilorado,  Arizona,  "  ^l?/(e?'.  Jovr.  Sci.,  December,  1883,  437.  Wheeler's 
Surrey,  Vol.  III.,  and  Supplement. 


336 


KEMP'S  ORE  DEPOSITS. 


spar  porphyry,  with  associated  grauite,  syenite  (Blake),  por- 
phyry, gneiss,  and  slates,  all  of  Archean  age.  The  veinlets 
ramify  through  the  strongly  altered  porphyry,  and  form  a 
stockwork,  which  furnished  the  principal  ores.  In  the  region 
are  also  Paleozoic  strata,  whose  upper  limestone  beds  are  re- 
ferred by  Blake  to  the  Carboniferous.  The  minerals  at  the 
mine  were  native  silver,  stronieyerite,  argentite,  sphalerite, 
galenite,  tetrahedrite,  bornite,  chalcopyrite,  pyrite,  quartz, 
calcite,  siderite,  and,  as  an  abundant  gangue,  barite. 

Graham  County  contains  the  Clifton  copper  district,  referred 
to  under  Example  2()a. 

Cochise  County  is  the  southeastern  countj',  and  contains  tlio 
Tombstone  district,  once  the  most  productive  of  the  precious 
metals  in  the  Territory. 

•^.ll.iU.  Tombstone.  A  great  porphyry  dike  up  to  70  feet 
thick,  faulted  and  altered,  and  carrying  above  tlie  water  lino 
in  numerous  vertical  joints,  or  partings,  quartz  with  free  gold, 
horn  silver,  and  a  little  pyrite,  galenite,  and  lead  carbonate. 
Curiously  enough,  in  the  porphyry  itself  and  far  from  the 
quartz  veins,  flakes  and  scales  of  free  gold  have  been  foniul, 
evidently  introduced  in  solution.  Ore  also  occurs  along  the 
side  of  the  dike.  There  are  also  other  fissures  parallel  with  tliis 
principal  dike,  and  still  another  series  crossing  these  and  the 
axis  of  the  great  anticline  of  the  district.  Connected  with 
these  fissure  veins  are  bedded  deposits  in  the  limestone,  along 
the  bedding  planes  or  dropping  from  one  to  another,  appearing 
to  have  originated  by  replacement.  Blake  offers  two  explana- 
tions of  the  first-mentioned  dike  deposit — either  that  the  dike 
itself  held  the  precious  metals,  or  that  the}'  came  from  the  pyrite 
of  the  adjoining  strata.  Several  other  mining  districts  of  less 
note  occur  in  the  count3\  The  important  copper  deposits  of 
the  Bisbee  region  have  already  been  mentioned  under  Example 
"ZQf.  The  most  productive  mine  of  the  territory  for  the  last 
year  or  two  has  been  the  Pearce  at  the  town  of  the  same  name, 
but  operated  by  the  Commonwealth  Co.  It  is  a  quartz  vein 
as  3'et  productive  of  oxidized  ores  containing  silver  and  gold. 

2.11.11.  Pima  County  is  the  central  county  of  the  southern 
tier,  and  has  Tucson  as  its  principal  city.  There  are  numbers 
cf  mines  of  the  precious  metals,  and  a  few  less  important 
copper  deposits. 


SILVER  AND  GOLD,   CONTINUED. 


337 


Yuma  County,  in  the  southwestern  corner,  has  some  luinea 
along  the  Colorado  River,  on  quartz  veins  in  metamorphosed 
rocks,  containing  silver  and  lead  minerals/  The Fortunu  mine 
is  at  present  the  chief  producer. 


NEVADA. 

2.11J3.  Geology. — Nevada  lies  almost  entirely  in  the 
Great  Basin,  only  the  western  portion  heing  in  the  Sierras. 
The  surface  i?  thus  largely  formed  by  the  dried  basins  of 
former  great  lakes,  principally  Lakes  Lahontan  and  Bonne- 
ville. A  large  number  of  ranges  extend  north  and  south 
through  the  State,  known  collectively  as  the  Basin  ranges. 
They  have  been  formed  by  block  tilting  on  a  grand  scale,  and 
present  enormously  disturbed  strata.  The  geological  sections 
exposed  are  of  surpassing  interest  (cf.  Example  3(i),  and  show 
Archean  and  Paleozoic  in  great  thickness.  In  these  mountains 
are  found  the  mining  distriCkts,  while  between  them  lie  the  alka- 
line plains.^ 


'  G.  F.  Becker,  Tenth  Cenma,  Vol.  XIII.,  p.  44.  G.  H.  Birnie,  'Castle 
Dome  District,"  Wheelers  Survey.  IHTfi,  p.  (\.  W.  P.  Blake,  "Tlie  (Jeology 
of  Tombstone,  Arizona,"  Ainer.  Inst.  Min.  Eiuj.,  X.,  8:34;  Eikj.  atid  Miii. 
Jour.,  June  24,  1882,  p.  328;  The  Silver  King  Mine,  a  short  mauograph, 
New  Haven,  ilarcli,  18H;l  Reo.  See  also  Eng.  and  Min.  Jour.,  April  28, 
1883,  p.  288.  J.  F.  Blandy,  "The  Mining  Region  around  Pre.scott,  Anz.," 
Trans.  Amer.  Inst.  Min.  Eng.,  XI.,  28(5;  Eng.  and  Min.  Jour.,  July  21, 
1883.  "On  Tombstone,  Arizona,"  Ibid.,  May  7,  1881,  p.  31(»;  Marcli  18, 
1882,  p.  145.  "  Silver  in  Arizona,"  General  Review,  Eng.  aitd  Min.  Jour., 
Sei)tember  21  and  2"),  1880,  pp.  172,  203.  "Central  Arizona,"  Ibid.,  April 
T.\,  1881,  p.  28.-).  O.  Loew,  "  Hualapais  District,"  Wheeler's  Survey,  1876, 
]i.  i)~).  B.  Sillimau.  "  Repin't  on  the  Mining  District  of  Arizona  near  tlie 
Hio  Colorado,"  Anwr.  Jour.  Sei.,  ii.,  XLL,  2S9;  see  also  Eng.  and  Min. 
Jour.,  August  11,  1877,  p.  111.  Raymond's  Rejiorts  and  those  of  the  Di- 
rector of  tlie  Mint  contain  notes  on  the  Arizona  mines. 

"  J.  Blake,  "The  Great  Basin,  '  Proe.  Cat.  Aead.  Sci.,  IV.,  27;-);  Amer. 
■lour.  Sci.,  iii.,  VI.,  59.  W.  P.  Blake,  "  On  the  Geology  and  Mines  of  Ne- 
vada" (Washoe  Silver  Region),  Quar.  Jour.  Geol.  Sei.,  Vol.  XX.,  p.  317. 
11.  G.  Clark,  "Aurora,  Nevada:  A  Little  of  its  History,  Past  r.nd  Present," 
School  of  Mines  Quarterly.  III.,  133.  G.  K.  (iilbert,  "A  Tlieory  of  the 
Earthquakes  of  the  Great  Basin,  with  a  Pmctical  Application,"  Anicr. 
Jour.  Sci,  iii.,  XXVII.,  49.  I.  C.  Russell,  "Geology  and  History  of  Lake 
I-uhontan,  a  Quaternary  Lake  of  Northwestern  Nevada,"  Monograph, 
XL,  U.  S.  Oeol.  Swvey;  also.  Third  Ann.  Rep.  Dir.  U.  S.  leol.  Survey, 
195.     C.  D.  Wolcott,  "  Paleontology  of  the  Eureka   District,"  iI/oHoyj«^)/i 


338 


KEMP'S  ORE  DEPOSITS. 


3.11.13.  Lincoln  County  is  in  the  southeastorn  corner,  and 
contains  a  number  of  small  mining  districts.  The  ores  are  iu 
general  silver-lead  ores  in  limestone,  or  veins  with  sulphuret 
ores  in  quartzite  and  granite.  Pioche  is  one  of  the  principal 
towns,  near  which  is  found  the  once  famous  and  now  reopeued 
Raymond  &  Ely  mine.  A  strong  fissure  cuts  Cambrian 
quartzite  and  overl3nng  limestone,  where  the  latter  has  not  been 
eroded,  and  is  occupied  by  a  great  porphyry  dike.  Along  tlu' 
contact  between  the  porphyry  and  the  wall  rock  the  chutes  of  ore 
have  been  found.  Mi.  Ernest  Wiltsee,  at  the  Montreal  meetiug 
of  the  American  Institute  of  Mining  Engineers,  February,  IH'.io, 
described  and  figured  the  Half  Moon  mine,  on  this  same  great 
fissure,  where  the  quartzite  still  retained  a  limestone  cap.  Tho 
ore-bearing  solutions,  on  reaching  a  shaly  streak  containing  a 
limestone  layer,  departed  from  the  fissure  and  followed  under 
the  limestone,  so  as  to  form  a  lateral  enlargement,  much  like 
those  described  and  figured  from  Newman  Hill,  Colorado,  under 
2.09.10.  The  Pahranagat  and  Tem  Pahute  districts,  still  fur- 
ther south,  have  had  some  prominence,  but  the  whole  region  is 
so  far  from  the  lines  of  transportation  that  the  conditions  are 
hard  ones.^ 

2.11.14.  Ney  County,  next  west,  has  an  important  miuiug 
center,  in  its  northern  portion,  around  the  town  of  Belmont. 
Quartzites  and  slates  rest  on  granites  in  the  order  named,  and 
in  them  are  veins  with  quartz  gangue  and  silver  chloride;:, 
affording  very  rich  ores.     Southeast  of  Belmont  is  Tybo.^ 

3.11.15.  White  Pine  County  lies  to  the  northeast,  and  con- 
tains the  White  Pine  district.  The  principal  town  is  Hamilton, 
about  110  miles  south  of  Elko,  on  the  Central  Pacific.  The 
Humboldt  range  is  prolonged  southward  in  some  broken  hills, 
consisting  chiefly  of  folded  Devonian  limestone.  At  Hamilton 
these  are  bent  into  a  prominent  anticline,  and  this  has  a  strout( 
fissure  crossing  the  axis.     The  geological  section  is  Devonian 

VIII.,  U.   S.    Oeol.   Survey.    Gilbert,    Wlieeler,    Lock  wood,   and  otlier.^, 
"  Eastern  Nevada  :  Notes  on   its   Economic;  Geology,"  Wheeh'r'.'i  Skitci/ 
Rep.  Prog.,  IHfJO,  71,  72:  also  Vol.  III.  and  Supi)lenient.     For  further  lit 
erature,  see  under  Exaiapk-  '•]<&. 

>  E.  P.    Howell.    Wheeler  H  Survey,    III.,  257.     G.  M.  Wheeler,    Reixirt. 
Wlieeler' s  Survey.  18(59,  p.  14. 

«  S.  F.  Emmons,  Surrey  of  the  Fortieth  Parallel,  Vol.  III.,  p.  3fl;5.     G.  K 
Gilbert,  "On  Belmont  and  Neighborhood,"  Wheelei''8  Survey,  III.,  36. 


SILVER  AND  GOLD,  CONTINUED. 


339 


limestone,  thin  oalcareous  shale,  thin  siliceous  limestone,  ar- 
gillaceous shale,  probably  Carboniferous  sandstone,  and  Carbon- 
iferous limestone.  The  ore  bodies  occur,  according  to  Arnold 
Hague,  in  four  forms,  all  in  the  Devonian  limestone:  (1)  in 
fissures  crossing  the  anticlinal  axis;  (2)  in  contact  deposits  be- 
tween the  limestones  and  shales;  (3)  in  beds  or  chambers  in 
the  limestone  parallel  to  the  stratification;  (4)  in  irregular 
vertical  and  oblique  seams  across  the  bedding.  The  ore  is 
chiefly  chloride  of  silver  in  quartz  gangue.  It  is  thought  by 
Mr.  Hague  to  have  probably  come  up  through  the  main  cross 
fissure,  and,  meeting  the  impervious  shale,  to  have  spread 
through  the  limestone  in  this  way.' 

Egan  Cafion  is  in  the  northern  part  of  the  county,  and 
shows  a  geological  section  of  granite,  quartzite,  and  slate  in  the 
order  named.  In  slates,  and  perhaps  extending  into  the  quart- 
zite, is  a  quartz  vein  five  to  eight  feet  wide,  carrying  gold  and 
silver  ores. 

Eureka  County  is  the  next  county  west  of  White  Pine.  The 
deposits  at  Eureka  have  already  been  described  under  "Lead- 
silver."  (Example  ;3G.) 

2.11.16.  Lander  Countj^  lies  next  west  to  Eureka.  The 
Toyabe  range  runs  through  it  from  north  to  south,  and  in  its 
southern  portion,  in  Ne}'  County,  contains  the  Belmont  depos- 
its. (See  above,  2.11.14.)  At  Austin,  which  is  8()  or  00  miles 
south  of  the  Central  Pacific  Railroad,  now  connected  with  it 
by  a  branch,  are  the  mines  of  the  Reese  River  district,  named 
from  the  principal  stream  near  by.  From  Mount  Prometheus, 
wliich  consists  of  biotite  granite  or  granitite,  and  which  is 
pierced  by  a  great  dike  of  rhyolite,  a  western  granite  spur  runs 
out,  known  as  Lander  Hill.  The  ore  bodies  are  in  this  hill, 
and  are  narrow  fissure  veins  with  a  general  northwest  and 
southeast  trend,  carrying  rich  ruby  silver  ores,  with  gray  cop- 
per, galena,  and  blende,  in  a  quartz  gangue  with  associated 
rhodochrosite  and  calcite.  They  are  also  often  faulted.  At 
tiraea  they  show  excellent  banded  structure.  Antimony  has 
recently  been  found  in  this  region. '^     (See  under  "Antimony.") 

'  J.  E.  Clayton,  "Tlie  geological  structure  and  mode  of  occurrence  of 
the  silver  ores  in  the  White  Pine  district,"  Cal.  Acad.  Sri.,  1V.,S9.  A. 
Hague.  Fortieth  Parallel  Survey,  Vol.  III.,  p.  409. 

'  S.  F.  Emmons.  Fortieth  Parallel  Survey,  Vol.  III.,  p.  84!». 


•i:  fti*-'' 


340 


KEMP'S  ORE  DEPOSITS. 


2.11.17.  Elko  County  lies  north  of  White  Pine  and  Eureka 
counties,  and  contains  the  Tuscarora    mining  district.     The 
deposits  are  high-grade  silver  ores  in  veins,  in  a  decomposed 
hornblende  andesite.^ 

Humboldt  County  is  the  middle  county  of  the  northern  tier, 
and  contains  a  number  of  mining  disrticts,  which  produce  both 
silver  and  gold  from  quartz  veins  in  the  Mesozoio  slate.  Small 
amounts  of  the  precious  metals  come  also  from  Washoe  County, 
in  the  northwest  ccruer  of  the  State.'' 

Churchill  County  adjoins  Lander  on  the  west,  and  pos- 
sesses a  few  silver  mines. 

Esmeralda  County,  in  the  southwest,  has  a  considerable 
number  of  rich  silver  and  gold  mines,  which  produce  high- 
grade  ores  from  veins,  with  a  quartz  gangue  in  metamorphic 
rocks,  slates,  schists,  etc.     (See  also  under  "Nickel.") 

2.11.18.  Storey  and  Lyon  are  two  small  counties  in  the 
western  central  portion  of  the  State,  but  the  former  contains 
the  most  important  and  interesting  ore  deposit  in  Nevada,  if 
indeed  it  is  not  the  largest  and  richest  single  vein  yet  discov- 
ered. 

2.11.10.  Comstock  Lode.  A  great  fissure  vein,  four  miles 
long,  forked  into  two  branches  '^bove,  along  a  line  of  faulting 
in  eruptive  rocks  of  the  Tortiarj'  age,  and  chiefly  andesites. 
In  the  central  part  of  the  vein  the  displacement  has  been  about 
3,000  feet,  shading  out,  however,  at  the  ends.  The  ores  are 
high-grade  silver  and  gold  ores  in  quartz,  and  occur  in  great 
bodies,  called  "bonanzas,"  along  the  east  vein.  Over  $325,- 
000,000  in  gold  and  silver  has  been  extracted,  in  the  ratio  of 
two  of  the  former  to  three  of  the  latter.  The  vein  lies  on  the 
easterly  slope  of  a  northeasterly  spur  of  the  Sierras.  West  of 
it  is  Mount  Davidson.  Theoutcroppings  lie  on  the  flank  of  the 
latter,  about  ()..500  feet  above  the  sea  and  \,h(){)  below  the  sum- 
mit. The  general  strike  of  the  vein  is  east  of  south,  and  it  dips 
east. 

Views  regarding  the  geology  of  the  Comstock  have  changed 
in  the  course  of  years,  as  they  have  been  influenced  by  the 
successive  writings  of  Von  Richthofen,  King,  Church,  Becker, 
and  Hague  and  Iddings,  the  points  in  especial  controversy 
being  the  determinations  of  the  rock  species. 


G.  F.  Becker,  Tenth  Consus,  Vol.  XIII.,  p.  34. 


Ibid.,  p.  33. 


SILVER  ANU  UuLD,   CONTIMEI). 


3il 


2.11.20.  It  may  be  remarked  that  the  whole  scheme  of  the 
classification  of  the  volcanic  (effusive)  rocks  rests  largely  jq 
Von  Richthofen's  early  studies,  and  that  perhaps  the  most  im- 
portant generalization  of  late  j'ears  is  due  to  the  work  of 
Hague  and  Iddings  on  the  same.  Von  Richthofen  (1805)  de- 
scribed the  ore  body  as  filling  a  fissure  on  the  contact  of  a  so- 
called  syenite,  and  an  eruptive  rock  that  he  called  "propylite." 
The  ore  and  gangue  are  thought  to  have  been  brought  up  from 
below  by  solfataric  action,  in  which  fluorine,  chlorine,  and 


sulphur  were  the  principal  dissolving  agents.  Clarence  King 
(18i)7-(;8,  published  in  18TU)  brings  out  forcibly  the  fact  that  the 
foot-wall  of  the  vein  approximates  closely  the  natural  contiima- 
tion  of  Mount  Davidson, and  contends  that  the  vein  filled  a  fissure 
between  the  syenite  of  which  Mount  Davidson  consists,  and  the 
late  Tertiary  eruptive  rocks  poured  out  against  its  flanks. 
He  traced  the  geological  succession  of  these  and  explained  the 
tilling  of  the  vein  by  solfataric  action,  attendant  on  a  thin  dike 
of  andesite,  which  forced  its  way  into  the  contact.     J.  A.  Church 


342 


KEMP'S  ORE  DEPOSITS. 


(1877)  thought  that  the  dlorite  (called  sj'enite  above)  of  Mouut 
Davidson  had  been  extruded  originally  in  thin,  horizontal 
sheets,  which  were  folded  in  east  and  west  folds.  This  was  to 
account  for  the  sheeting  of  the  rocks  of  the  lode  as  now  seen. 
On  the  diorite  was  poured  out  next  the  propylite,  likewise  in 
successive  horizontal  sheets.  Then  they  were  all  tilted  along 
north  and  south  axes,  and  eruptions  of  andesite  penetrated  be- 
tween their  sheets  in  very  large  amount.  Further  movements 
forced  the  convexities  of  tho  first-formed  folds  against  the  au- 
desites,  and  crowded  their  substance  sidewise,  to  some  extent, 
into  the  synclinals.  This  movement  slightly  parted  the  bedy, 
affording  watercourses  through  which  rose  siliceous  waters. 
These  dissolved  away  the  neighboring  beds,  leaving  extensive 
quart/  bodies  in  their  places.  They  also  removed  the  andesite 
caps.  No  ore  was  formed  as  yet.  Now  followed  great  tra- 
chyte eruptions  on  the  east,  which  loaded  the  hanging  wall  of 
the  lode  so  heavily  as  to  cause  a  downward  movement  of  it  on 
the  foot,  making  a  new  series  of  openings,  and  into  these 
poured  the  ore-bearing  solutions  which  brought  the  precious 
metals.  No  one  who  has  intelligently  followed  this  explana- 
tion will  doubt  that  Mr.  Church  has  shown  great  ingenuity, 
and  yet  it  is  natural  to  prefer  to  avoid  so  long  and  involved  an 
hj'pothesis,  if  a  simpler  course  will  lead  to  tho  same  results. 
At  the  time  of  Mr.  Church's  visit  the  workings  were  becom- 
ing very  deep,  and  the  great  heat,  which  has  been  since  such 
an  obstacle,  was  manifesting  itself.  Flooded  drifts,  it  was 
thought,  had  been  observed  to  grow  hotter,  and  from  this  the 
hypothesis  of  kaolinization  was  conceived.  It  was  that  the 
kaolinization  of  the  feldspar  in  the  deeply  buried  rock  oc- 
casioned the  heat  of  the  lode. 

2.11.21.  G.  F.  Becker  (1879-82)  comments  on  the  exces- 
sive alteration  which  the  rocks  have  undergone,  as  it  figures 
largely  in  his  hypothesis  of  origin.  He  then  traces  the  results  of 
faulting,  and  shows  that  under  conditions  like  those  present  the 
surface  would  tend  to  assume  a  logarithmic  curve,  which  coin- 
cides surprisingly  well  with  the  present  outline  of  the  country. 
After  describing  the  lode  itself,  the  orfgin  of  its  metalliferous 
contents  is  traced  as  follows.  Waters  under  hydrostatic  pres- 
sure from  the  heights  to  the  west  are  supposed  to  have  perco 
lated  toward  the  lode,  passing  through  deeply  buried  regions 


SILVER  AND  GOLD,  CONTINUED. 


343 


of  heat.  They  were  probably  diverted  from  risiug  directly 
tlirough  the  lode  by  an  ^!mpervious  clay  seam,  and  v/ere  thus 
forced  to  traverse  the  diabase  hanging,  relieving  it  in  pas- 
sage of  the  metals,  which  were  afterward  deposited  in  the 
higher  portions  of  the  lode.  The  metals  themselves  were 
probably  largely  derived  from  the  augite  of  the  rock.  Mr. 
Becker  had  as  an  associate  Dr.  Carl  Barns, who  studied  the 
beat  phenomena  (especially  the  hypothesis  of  kaolinization)  and 
the  electrical  manifestations  of  the  lode.  The  result  of  Dr. 
Barus's  careful  experiments  threw  great  doubt  on  kaolinization 
as  a  source  of  heat.  The  electrical  experiments  were  not  satis- 
factory. They  were  carried  on  also  at  Eureka,  Nov.,  but  no 
very  definite  results  were  reached. 

2.11.22.  The  correct  determination  of  the  eruptive  rocks 
neighboring  to  the  Comstock  has  been  of  great  importance,  not 
alone  because  of  their  scientific  interest,  but  as  bearing  on  the 
fact  as  to  whether  the  lode  itself  was  a  conf;act  fissure  between 
two  different  rocks,  or  whetbor  it  was  simply  a  fissure  vein.  It 
is  worthy  of  note  that  in  connection  with  it  Von  Ricbthoten  de- 
veloped one  of  the  first  important  attempts  to  classify  the  vol- 
canic rocks,  and  that  Hague  and  Iddings  have  finally  urged 
that  the  peculiar  crystalline  textures  of  all  eruptive  rocks  de- 
pend primarily  on  the  rate  of  cooling  and  pressure  {i.e.,  depth 
below  the  surface)  under  which  they  have  solidified,  destroying 
thus  the  time  element  in  classification.  This  is,  to  be  sure, 
an  old  idea,  but  it  gains  its  best  confirmation  from  the  Com- 
stock. Von  Richthofen,  in  his  report  to  the  Sutro  Tunnel 
Company,  and  in  his  later  memoir  on  "The  Natural  System  of 
the  Volcanic  Rocks"  {Cal.  Acad.  .Sei.,  18*57;  q\ho Zeitschrift 
(/.  d.  geol.  (ze.seZ/.,  1808,  GG3),  distinguished  in  the  Washoe  dis- 
trict syenite,  metamorphic  rocks,  quartz-porphyry,  propylite, 
!-anidine-tracbyte,  and  very  subordinate  ande.site.  Mr.  King 
referred  much  of  the  propylite  of  Von  Richthofen  to  andesite, 
but  retained  the  propylite  as  a  distinct  species,  although  re- 
marking the  close  atiinities  of  the  two.  The  quartz-porphyry 
be  called  quartz-propylite.  In  other  respects  no  changes  are 
iutroduced.  Zirkel  {Fortieth  Parallel  Survey,  Vol,  VI.)  de- 
termined the  syenite  as  granular  diorite,  and  while  accepting 
hornblende-propylite  and  quartz-propylite  as  separate  species, 
called  the  greater  part  of  the  quartzose  rock  dacite.     He  intro- 


m 


344 


KEMPS  QUE  DEPOSITS. 


duced  for  the  first  time  augite-aiiflesite,  rhyolite,  and  basalt. 
Mr.  Church  paid  less  atteution  to  lithology,  and  used  the  terniK 
of  his  predecessors  somewhat  loosely.  Mr.  Becker  makes  the 
foUowiug  classifications:  granular  diorite,  porphyritic  diorite, 
micaceous  diorite-porphyry,  quartz-pi>rphyry,  earlier  diabase, 
later  diabase, earlier  hornblende-andesite,  ai.yite  audeyite,  later 
hornblende-andesite,  and  basalt.  In  this  it  will  be  seen  that 
several  new  varieties  are  introduced,  but  the  main  mass  of 
Mount  Davidson  was  still  considered  diorite,  and  the  vein  was 
thought  to  lie  between  this  and  some  of  the  other  species  men- 
tioned, especially  diabase.  In  1S85,  Arnold  Hague  and  J.  P. 
Iddings  completed  new  microscopal  studies  upon  the  mateiials 
collected  bj'  Mr.  Becker,  and  the  results  were  published  as 
Bulletin  17  of  the  United  States  Geological  Surreij  ("On 
the  Development  of  Crystallization  in  the  Igneous  Rocks  of 
Waslioe,"  etc.).  These  two  writers  had  had  more  to  do  with 
the  eruptive  rocks  of  the  Great  Basin  and  the  Pacific  slope  than 
anj'  other  geologists,  and  hence  brought  to  the  review  an  ex- 
ceptional experience.  Nowhere  else  in  the  world  are  such  ex- 
posures and  thorough  sections  afforded,  alike  in  depth  and  in 
horizontal  extent.  Th3y  proved  that  the  diabase  and  augite- 
andesite  shade  into  each  other,  the  differences  in  crystallization 
being  due  to  depth ;  that  the  hornblende  of  the  so-called  diorite 
was  largely  secondary  from  original  augite,  being  derived  by 
paramorphic  change  (uralitization),  and  that  the  diorite  was  a 
structural  variety  of  the  diabase;  that  the  porphyritic  diorites 
shade  into  the  earlier  hornblende-andesites,  and  are  structural 
varieties  of  them  ;  that  the  mica-diorites  and  hornblende-ande- 
sites are  related  in  the  same  way;  that  the  assumed  pre- 
Tertiary  age  of  the  quartz-porphyry  was  unwarranted,  and 
that  it  was  partly  dacite  and  partly  rhyolite,  the  two  shadinj^ 
into  each  other;  that  the  younger  diabase,  so-called,  of  the  sub- 
surface dike,  was  identical  with  the  rock  elsewhere  occurring 
on  the  surface  and  called  basalt,  and  was  really  a  basalt,  owing 
to  its  holocrystalline  character  to  its  depth;  and  finally — the 
most  important  conclusion  of  all  in  this  connection,  although 
the  other  conclusions  are  among  the  most  important  advances 
made  in  late  years — "that  the  Comstock  Lode  occupies  a  line 
of  faulting  in  rock  of  the  Tertiary  age.  .'uvl  cannot  be  con- 
sidered as  a  contact  vein  between  two  different  rock  masses." 


SIL  VER  AND  GOLD,  CONTINUED. 


345 


The  crystalline  structure  of  the  Washoe  rocks  has  been  sub- 
8e«inently  treated  by  Mr.  Becker,  ("The  Washoe  Rocks," 
/;////.  Cal.  Acad.  Svi.,  Vol.  II.,  p.  015,  January,  1HS7;  "Tex- 
ture of  Massive  Rocks,"  Amcr.  Jour.  Sci.,  ii.,  Vol.  XXXIII., 
p.  50,  1887.)  The  various  structures — granular,  porphyritic, 
and  glassy — are  referred  more  to  differences  in  composition  and 
fluidity  than  to  circumstances  of  solidification.* 

'  G.  F.  Becker,  "  Geoloj^y  of  tlie  L'omstock  Lode  and  the  Wuslioe  Dis- 
trict," Monotjvitph  TIL,  V.  S.  Geol.  Survri/.  Rec.  See  also  Eiig.  (iii<l Min. 
Jour.,  JIiuvli  1,  1SM4,  J).  1(12;  //.  Aini.  Rep.  Dir.  U.  S  Urol.  Sunri/.  Rec. 
J.  A.  Churcli,  Tlie  Comtiiock  Lodv:  Itn  Formation  and  hinforij.  New  York: 
John  Wiley  &  Sons.  Reviewed  in  En(j.  anil  Min.  Jour.,  Fehniary  21,  1880 
p.  ;i!tT.  See  also  sliorter  papers  in  t\w.  Eutj.  (dkI  Min.  Jour.,  Deceniher 
38.  1HT8,  p.  406;  July  10,  1879,  p.  35;  Deceniher  12,  I88ri,  p.  39T;  January, 
2;<,  1880,  p.  .")2.  "On  the  Changes  in  the  Conistock  Vein,"  Eixj.  and  Min. 
Jour.,  December  18,  188(),  p.  434;  "Tlie  Discovery  of  the  Conistock  Lode," 
IhiiL,  December  5  and  1!).  1891.  and  otlier  pipers  in  1892  by  Dan  De  Quille. 
Habile  and  Lldinffs,  "On  the  Development  of  Ciystallization  in  the  Tg- 
neous  Rocks  of  Washoe,  Nevada,"  etc.,  Bull.  17,  U.  S.  Geol.  Survey.  See 
also  Bull,  a,  Cal.  Acad.  Sci.  and  En(f.  and  iV/H.  ,/o»?'.,  Decend)er  11. 
1880,  p,  415.     Charles  Howard  Sham,  "The  Story  of  the  Mine,"  Hist. 


hading 


)e  con- 
)> 


CHAPTER  XII. 

THE  PACIFIC  SLOPE:   WASHINGTON,  OREGON,  AND  CALIFORNIA. 

WASHINGTON. 

3.12.01.  Oeology. — Little  is  available  in  the  way  of  system- 
atic descriptions  of  the  geology  of  Washington,  and  an  attrac- 
tive tiold  remains  to  be  developed.  The  ranges  of  the  Rocky 
Mountains  extend  across  the  panhandle  of  RU.  ho  and  show  in 
northeastern  Washington,  atfording  considerable  amounts  of 
ores.  They  are  prevailingly  granite  and  gneiss,  which  liave 
escaped  being  covered  by  the  enormous  volcanic  outbreaks  of 
Tertiary  and  later  time.  West  of  the  granites  a  great  plateau 
coiintry  of  somewhat  diversified  surface  is  met.  It  seems  to 
have  been  an  ancient  lake  basin,  but  is  now  covered  by  igneous 
rocks  and  deposits  of  volcanic  tuff.  Still  farther  west  the 
Cascade  chain  forms  the  central  divide  of  the  State.  The 
rocks  are  granites,  flanked  by  Paleozoic,  Mesozoic,  and  nieta- 
morphic  strata,  much  like  the  Sierras  of  California.  They 
were  upheaved  in  large  part  before  the  Cretaceous,  and  since 
then  other  movements  have  occurred.  There  are  vast  develop- 
ments of  igneous  rocks,  forming,  as  at  Mount  Rainier,  some  of 
the  highest  American  peaks.  West  of  the  Cascade  range  is  a 
great  valley  formerly  marking  a  drainage  sj'stem,  but  now 
covered  partly  by  glacial  drift  and  partly  by  the  waters  of 
Puget  Sovmd.  The  glacial  deposits  are  enormous,  and  render 
the  problem  of  working  out  the  geology  very  difficult.  Some 
glaciers  remain  on  the  heights  even  to  the  present  day.  West 
of  the  Puget  Sound  Basin  is  the  northerly  extension  of  the 
Coast  range,  locally  called  the  Olympics,  and  largely  Creta- 
ceous and  Tertiarj^  strata.' 

'  G.  F.  Becker,  Tenth  Census,  Vol.  XIII.,  p.  37.     G.  A.  Betlmne,   First 
Ann.  Rep.  State  Qeol,  1891.     A.  Bowman,  "Mining  Developments  on  t'le 


Tilt:  PACIFIC  SLOPE. 


347 


'^.12.02.  Good  descriptions  of  the  ore  dopositn  of  WRshington 
art*  greatly  needed.  The  First  Annual  Keixnt  of  the  State 
Otologist  has  little  of  scientilic  value,  and  the  other  accounts 
ari'  more  or  less  ohsolete.  There  are  gold  plac^ers  in  Vakinia, 
StHvena,  and  Kittitas  counties,  largely  worked  hy  Chinese. 
But  in  Okanogan,  Snohomish  and  Stevens  counties,  in  the 
northeast,  the  developments  of  deep  mining  for  silver  ores, 
although  recent,  are  considerable.  The  Monte  Cristo  veins 
alTord  great  (juantities  of  refractory  and  rather  low  grade  ores, 
friiin  very  prominent  veins.  The  chief  country  rock  is  granite, 
but  numerous  dikes  of  more  basic  varieties  are  present.  The 
veins  are  largel)  in  metamorphic  rocks  and  contain  the  usual 
sulphides  in  cpiartz  gangue.' 


OREGON. 

:i.  12,03.  OcoJogi/. — Northeastern  and  northern  central 
Oregon  are  formed  by  a  prolongation  southward  of  the  igneous 
plateaus  of  Washington.  Slates  and  granite  appear  in  Baker 
County  on  the  east,  in  the  Blue  Mountains,  and  the  geology 
soi-ms  to  resemble  the  Si(M'ras.  All  southeastern  Oregon 
belongs  in  the  Great  Basin,  which  comes  north  from  Nevada, 
but  is  better  watered  than  the  southern  portion.  It  is  traversed 
by  several  subordinate  ranges  of  the  block-tilted  basin  type. 
Of  these  the  Stein  Mountains  are  the  most  prominent.  The 
general  surface  is  formed    by  Quaternary  lake    deposits  and 


Northwest  Pacific  Coast  and  their  wider  Bearing,"  Trans.  Amer.  Inst. 
Mill.  Eng.,  XV.,  707.  J.  MacFarlane,  0vol.  Railiraij  Guide,  second  edition, 
p.  'J(i2:  notes  by  Puuipelly,  WilHs,  and  otliers.  Hec.  J.  S.  Newberry, 
"(li'ology  and  Botany  ol'  the  Northern  i'aeilic  Raih-oad,"  rr((;(.s.  iV.  Y. 
Ai'iid.  Sci.,  III.,  1884,  p.  25;j.  C.  A.  White,  'Piiget  tJroup  of  Washing- 
tun."  Aincr.  Join:  Sci..  iii.,  XXXVI..  44!5.  B.  Willis,  "Our  Grandest 
^lountain  and  Deepest  Forest,"  »St7/oo/  of  Mines  (^ini rterlij.  \III.,  V)2. 
"  Report  on  tlie  Coal  Fielils  of  Washington  Territory,"  Tenth  Census,  Vol. 
XV.,  p.  759.  "Some  Coal  Fields  of  Puget  Sound," XVI TF.  Ami.  Reji.  Dir. 
i.  S.  Geol.  Snrveif,  Part  III.,  ;i!);j.  "Cliangesof  River  Courses  iu  Wash- 
ington Territory  due  to  Glaciation,"  Bull.  40,  U.  S.  Oeol.  Survey.  "  Drift 
Phenonienaof  Puget  Sound."  Bull.  Geol.  Soe.  Amer.,  IX  ,  III.,  1898. 

'  (f.  A.  Bethune,  First  Ann.  Rep.  State  Geol.,  189:.  C.  N.  Fenuer, 
"The  Monte  Cristo  District,  Snohomish  County, "  Sc/iooi  o/  ^[ines  Qiiar- 
tirhj,  November,  1892.  "The  Mines  of  Kittitiis  County,"  Eng.  and  Min. 
Jour.,  Deceml)er  24,  1892,  p.  G08.  F.  L.  Nason,  "The  xVuriferous  Gravels 
of  the  Upper  Columbia  River."  Eng.  and  Min.  Jour.,  March  21,  1896. 


I 


:J48 


h'h'MPS  (HiH  /tKI'OSfTS. 


groat  outbrcakH  of  igncoiiH  roclcH.  WoHt  of  the  huHin  and  the 
plateau  tlie  Cascade  rangi?  traverH«^H  tlie  State,  and  in  cMit  l)y  the 
Columbia  River  on  the  north  and  the  Klamath  on  the  Moutli. 
The  range  conMiHts  of  granite  and  metdnmrpbic  roekH,  etc.,  the 
latter  ohieHy  MeHOZoic.  In  northern  Oregon  a  broad  valley 
intervenes  between  the  Caseade  and  the  ('oast  ranges,  but  in 
the  southern  part  the  two  ranges  run  together,  and  their  dis- 
tinction luiH  been  only  partly  worked  out.  (See  Hn//.  -/•/,  /', 
»S'.  (icol.  Siirrc!/.)  lu  the  Count  range  Cretaceous  and  Tertiary 
strata  jiredominate.' 

^.1^.04.  Oregon  is  an  important  producer  of  gold  both  from 
placers  and  fioni  veins.  Baker  County,  on  the  east,  ])resent8 
the  characteristic  placers  and  gold  (piartz  of  the  California 
Sierras,  and  is  the  most  productive  section  of  the  State.  Grant 
and  Josephine  counties  also  have  placers,  and  smaller  amotnits 
come  from  a  few  others.  In  the  extreme  southeast,  near  the 
California  line,  is  Curry  County,  coTitaining: 

3.1"^. Of).  Example  4ia.  Port  Orford.  Auriferous  beach 
sajids  at  the  foot  of  gravel  clitfs,  and  shifting  with  the  wItkIs 
and  tides.  At  Port  Orford  the  ocean  has  access  to  great  sea 
clift's  of  gravel  whicb  it  breaks  down  by  the  force  of  the  waves. 
A  sorting  action  tnsues,  performed  by  the  undertow  and  the 
littoral  current.  The  heavier  gold  dust  is  concentrated  and  is 
gathered  up  by  the  miners  at  low  tide.  Some  submarine  work 
has  also  been  attempted.     The  j)roduct  is  not  great,  and  the 

'  (f.  F.  Bt'ckor.  'Jriith  rciisus.  Vol.  XIII..  p.  2T.  T.  ("oiidoii,  "OnSotnt' 
Points  CoiiiK'C'teil  with  the  Tgiieous  Eruptions  along  the  ('iiscudeJlouuttiiiis 
of  Oregon/' ^Imer.  JoHr.  Set.,  iii..  XVIII.,  40«.  J.  H.  Diller,  "Notes  .mi 
the(Jeol()gy  of  Nortliern  falifornia."  Hull.  ./.?,  U.  S.  Ocol.  Sxrvcif.  "A 
Geological  Heeonnai.ssiince  in  Northwestern  Oregon,"  XVII.  A)iv.  Rep.  l\ 
S.  Gi'dl.  Sum'!/,  Part  I.,  447,  with  notes  ou  the  Eeononiie  (}eology  J.  ('. 
Fremont,  "Observations  on  the  Roeky  Mountains  and  Oregon,"  ^W'C. 
Joitr.  Sci.,  ii..  III.,  193.  George  Gibhs,  "Notes  on  the  (ieology  of  tlie 
Country  Ea.st  of  the  Cascade  Jhnnitains,  Oregon,"  Antcr.  Jour.  Sci.,  ii., 
XX.,  '275.  ,T.  Leconte,  "On  the  (Jreat  Lava  Flood  of  the  West  and  on  (lie 
Structure  and  .Age  of  the  Cascade  Mountains,"  Ainer.  Join:  Sci.,  iii., VIII., 
I(i7,  'i'A}.  C.  King,  Fortictli  I'dntllcl  Skcvcij,  Vol.  I.  J.  MacFarlanc,  Ocd. 
Railway  Guide,  p.  3t0.  J.  S.  Newberry,  Pacific  R.  R.  Reports,  Vol.  VI  , 
pp.  1-78.  I.  C.  Russell,  "A  Geological  Reconnai.ssance  in  Southern  Ore- 
gon," IV.  Aim.  Rei>.  Dir.  U.  S.  (ieol.  Survey,  pp.  4;}r)-4()3.  G.  O.  Sniitli, 
••The  Rocks  of  Mt.  Rainier,'  Idem,  41B.  "Glaciers  of  Mt.  Rainier." 
XVIII.  A)iii.  Rep.  U.  S.  Geol.  Siu-vey,  II.,  349. 


TIIK  PACfFW  SLOPE. 


349 


dt'posit  is  chioHy  iutiirewtiug  in  ita  noiontiHc  l)oariii^.  It  iuiih 
alonj?  into  California  an  woll.  Aurifenmn  Haiuln  occur  at 
Yakutat  Bay,  Alawka.'  Tlio  gold  of  the  Potstlam  sandHlones 
of  the  Black  Hills  has  heen  ex})luine(l  in  a  HiniiUir  way,  hut 
later  ohservatioiiH  have  niodlHed  the  liA'pothesiH.  The  nmgnetite 
smikIh  which  were  referred  to  under  '-i.();i.i;{  furnish  8oniotlung 
<if  a  paralleh" 


CALIFORNIA. 

•^.12.06.  Oeolo{iii. — The  topography  and  geology  of  northern 
California  have  heen  hut  recently  made  clear.  Diller  couwiders 
tliiit  the  southern  end  of  the  Cascade  range  is  Mount  Shasta; 
that  the  Sierras  proper  terminate  near  th«^  north  fork  of  the 
Feather  River,  hut  the  lino  is  continued  ahout  fifty  miles  far- 
ther north,  in  the  Lassens  Peak  volcanic  ridge,  and  that  all 
ehe  west  and  st)uth  of  Mount  Shasta  helong  to  the  Coast  range. 
Central  California,  as  is  well  known,  has  the  Sierras  on  the 
east,  the  great  Sacramento  Valley  in  the  middle,  with  the 
Coast  range  on  the  west.  The  arid  regions  of  the  Great  Basin 
just  toucli  the  northeastern  corner,  hut  on  the  southern  extrem- 
ity they  swing  around  and  form  a  large  part  of  the  State.  The 
Great  Basin  portion  is  formed  hy  Quaternary  lake  deposits. 
TliH  Sierras  consist  of  central  granite  and  gneiss,  with  great 
developments  of  slates  and  eru})tives  on  their  flanks.  The 
excessive  metamorphism  has  largely  destro3-ed  the  fossils,  hut 
enough  have  heen  found  to  prove  that  while  in  large  part 
Jurassic  and  Carboniferous,  Triassic  and  Silurian  representa- 
tives are  also  present.  The  western  slopes  have  the  mantles 
of  gravel,  which  have  furnished  sonuich  gold,  and  with  theseare 
large  outflows  of  hasalt.     The  upheaval  of  the  Sierras  occurred 

~^'  J.  Stanley-Browne,  Nat.  GeoijrTJlmj.,  Vol.  111.,  ISKi-liW,  18!tl. 

-  (i.  F.  15ecker,  I'ciith  Census,  Vol.  XIII.,  p.  27,  general  uccouiit  of  Ore- 
gon W.  P.  Blake,  "Ciolcl  and  Platinum  from  Cape  Blanco  (Port  Or- 
i<>vi\),"  Anif.')'.  .Jour.  Sci.,  li.,  XVllL,  IT)*').  "Remarks  on  the  Extent  of 
tlie  Gold  Regions  of  California  and  Oregon,"  etc.,  Amer.  Jour.  Sci..  ii., 
XX.,  72.  A.  W.  Chase,  "The  Auriferous  Gravel  Deposits  of  Gold  Bluir.s, 
Ciilifornia,"  Cal.  Acad.  Sci.,  1874;  Anwr.  Juur.  Sci.,  iii.,  VIII.,  8(57. 
"Dredging  for  Gold,"  Eng.  ami  Min.  Jour.,  June  28.  ISm,  ]).  ;iO().  B.  Sil- 
linian,  "Clierokee  Gold  Wa.shings,"  ^Iwic/-.  Jour.  Sci.,  iii.,  VI.,  1152.  W. 
P.  Watts,  "Sands  in  Santa  Cruz  County,  California,"  i?f/>.  Cal.  State. 
Mineralogist,  1890,  p.  622. 


'(        r? 


350 


KEMP'S  ORE  DEPOSITS. 


W^ 


before  the  middle  Cretaceous  time.  The  Coast  range  con- 
tains large  areas  of  sandstones,  cherts,  and  lavas,  probably  of 
Jurassic  age,  as  well  as  Cretaceous  and  Tertiary  strata.  They 
were  upheaved  in  post-Miocene  time.  Great  outbreaks 
of  andesite  also  occurred,  and  later  basalts.  The  prin- 
cipal product  of  California  is  gold,  but  there  are  dis- 
tricts which  have  furnished  considerable  silver,  and  which  are 
first  described  in  order  to  lead  up  to  gold.  The  copper  and 
iron  resources  have  already  been  mentioned,  and  the  mercury, 
antimony,  and  chromium  deposits  remain  for  description  after 
the  precious  metals.' 

'  G.  F.  Becker,  "Notes  on  the  Early  CretaceouM  of  Califonua."  .hz/cr. 
.lour.  Sci.,  iii.,  II.,  20).  -'Antiquities  from  uutler  Tuoluiuiie  Tal)Ie  Moun- 
tain, California,"  Bull.  Gcol.  Soc.  Anwr.,  II. ,189.  "Cretaceous  Metaiuoiphic 
Kocksof  California,"  ADier.  Jour.  Sci.,  iii.,  XXXI.,  848.  "Structure  of  a 
Portion  of  the  Sierra  Nevada  of  California,"  Ihdl.  Goal.  Soc.  Ainer.,  II..  .",0. 
"Notes  on  the  Stratigraphy  of  California,"  Bidl.  1!>,  U.  S.  Geol.  Siirrci/. 
W.  P.  Blake,  "  Notes  on  California,"  Anicr.  Jour.  Sci.,  ii.,  XVIII.,  411.  W, 
H.  Bre\vere])itoniizes  Whitney's  report,  Aincr.  Jour.  Sci. ,ii.,  XLI.,  '2;U;iils() 
53.")1.  J.  D.  Dana,  "Notes  on  Upi)er  California,  "  Aiiicr.  Jour.  Sci.,  ii.,  \  II., 
376.  J.  S.  Diller,  "Geology  of  the  Lassen  Peak  District,"  Eighth  Ann.  Rep. 
Dir.  V.  S.  Gcol.  Suvvaj,  i)p.  401,  4;r).  "On  the  Cretaceous  Rocks  of  North 
ern  California,"  Amcr.  Jour.  .SV('.,iii.,  XL.,47(').  "On  the  Geology  of  Ni mli- 
ern  California,"  P*w.  P//?7.  Soc.  of  Wash.,  January  IH,  188(5;  Abstract, 
Amer.  Jour.  ScL,  iii.,  XXXIII.,  ir)2.  "Geology  of  the TaylorvillehVt^ion, 
Plumas  County,"  Hull.  Gcol.  Soc.  Avicr.,  III..  ;!69.  G.  K.  Gilbert,  'The 
Recency  of  Certain  \<,'.'anoes  of  the  Western  United  States, "  Anivr.  Assoc. 
Adv.  Sci.,  XXIII.,  29.  A.  Hyatt,  "  .Tura  and  Trias  of  Taylorville.  CaL 
fornia,"  77/(//.  Gcol.  Soc.  Auicr.,  III.,  ;59r».  William  Trelan,  State  ^fiiiiMal- 
ogist,  ^1»».  Rep.,  18S(),  and  following,  e.sjiecially  18!I0,  geology  by  counties. 
J.  Leconte,  "Post-Tertiary  Elevation  of  the  Sierra  Nevadas,  shown  b\  the 
River  Beds,"  Amcr.  Jour.  Sci..  i.i.,  XXXII.,  1(>T.  "Old  River  Bedsof  Cal 
ifornia,"  Ibid.,  iii.,  XIX..  190  iii..  XXXVIII.,  2(51.  "Extinct  Volcan.ies 
about  Lake  Mono,  and  their  Relations  to  the  Glac'ial  Dri*'*;.",  Ibid  .  ii'.. 
XVIII..  3.1.  .Jules  Marco'  "Re}Kirt  oti  the  Geology  of  a  Portion  of  South 
ern  California,"  Wlieclcr  Snri'ctf.  Ann.  Rep.,  187(5,  Apj).,  p.  I.kS.  .1  1'. 
Mills,  "Stmtigraphy  and  Succe.ssion  of  the  Rocks  of  the  Sierra  Nevada  <>f 
Califortwa,"  Bull.  Geol  Soc.  Amcr.,  III.,  413.  E.  Reyer,  Thcorctische 
Geologic,  p.  r)3T,  188S.  I.  C.  Russell,  "The  Quaternary  History  of  Xoiw 
Valley,  California."  Eighth  Anu.  Rep.  Dir.  U.S.  'leol  Survci/.  pp. ','(5:  I'll. 
H.  W.  Turner,  "The  Geology  of  Mount  Diablo,  with  the  Chemistry  of  the 
Rocks  by  W.  H.Melville,"  Bull.  Gcol.  Soc  Awcr..U..  3M3.  "Further  (on- 
tributionsto  theGeology  of  the  Sierra  Nevada,"  XVIIl.  Ann.  Rep.  Dir  V. 
S.  Geol.  Survey,  Part  "  ,  p.  521.  Rec.  "The  Granitic  Rocks  of  the  Si.  rni 
Nevada,"  Jour.  Gcol,  VII.,  141.  Rec.  J.  A.  Veatch,  "Notes  on  a  \  i-^it 
to  the  ;\rud  Volcanoes  of  the  Colorado  Desert  "  etc  ,  Amer.  Jotir.  Sci ,  ii., 


THE  PACIFIC  SLOPE. 


351 


^e  con- 
ably  of 
,     They 
itbreaks 
le    prin- 
ire    (lis- 
bicb  are 
iper  and 
mercury, 
ion  after 


lia,"  .!(/(('/•. 
able  Mduii- 
etainurpliii-' 

•UL'tUVl!  Ill   il 

ner.s  II  ■  •"■" 
eol.  Siirrcii. 
IL.Ul.  \V- 
J.,  2;U:als() 
:c'/.,ii..VlI.. 
h  Ann.  Rep. 
iksof  Noitli- 
jry  of  Noith- 
lil;  Abstnu't, 
UeEo^ion, 


VI 

lilbert, 


•■The 


rville,  CaK- 
ate  Miiieval- 

bv  coil II ties. 
I, own  bv  llie 

IVdson'al 
|.,t  Vdlciiimes 
/;)(■(/.  ii'  • 


lion 


of  I 

l,-.8. 


•oiith 


l-a  Nevail 


Thcoy 


lor 


V  of  >  <">" 


pp. 


'2('.T   101. 


Iniistry  < 
thor 


,1'  the 

(  oil- 


Rep.  D!'    f' 
of  the  !^i''""^ 


-uv 


ks  on  a 


V  isit 


2.12.07.  Calico  District.  Deposits 
of  silver  chloride  in  fissure  veins,  aad 
iu  small  fractures  and  pockets  in  lipa- 
riti'3.  tuflt's  and  sandstones,  probably  of 
tln'  Pliocene  series.  They  occur  in 
Southwestern  California,  in  that  portion 
of  the  State  belonging  rather  to  the 
Great  Basin  than  to  the  Pacif  lope. 
An  immense  outbreak  of  1  p;  ite  has 
formed  a  seri  s  of  elevations,  and  the 
attendant  tuffs  are  extensively  devel- 
oped. The  ore  is  thought  by  Lindgren 
to  have  come  in  heated  solution  from 
below  and  to  have  filled  the  fissures  and 
overflowed,  forming  the  surface  de- 
posits in  the  tuffs.  (Cf.  Silver  Cliff, 
Colorado. ) 

'2. 12.08.  Likewise  iu  the  desert  re- 
gion, a  gold  camp  has  sprung  up  at 
Raiulsburg,  in  Kern  County.  Mica 
schists  form  the  countrj'rock  of  a  series 
of  hills  that  rise  above  an  abandoned 

XX\'\..  288.  J.  D.  V/liitney  and  others,  reports 
of  tlie  California  Geological  Survey,  issued  at 
faiiiliridKe,  Mass.  L.  (1.  Yates,  'Notes  on  the 
(!e(ili>y;y  and  (Scenery  of  the  Islands  forming 
the  Southern  Line  of  the  Santii  liar1)ara  Clian 
\w\:'  Amer.  G€ol.,V.,4'6.  The  United  States 
Tiei (logical  Survey  has  prepjxred  a  number  of 
folios  on  the  geology  of  the  gold  belt,  wliich 
are  invaluable  to  all  who  are  interested  in  tlie 
reKioii.  Each  embraces  a  geological  descrip- 
tion and  maps,  which  severally  show  the  topo- 
Krii|iliy,  geology,  anil  mineral  rf'sources.  The 
folliiw  iiig  have  been  i.ssued  and  can  be  ob- 
taiuid  at  25  cents  each  by  addressing  the  Di- 
rector of  the  U.  S.  Geological  Survey,  Wash- 
iii^itnn,  D.C.  (the  Nevada  City  Folio  is  r»0 
oeiiis):  Placerville,  Sacuamento.  Jacks<m, 
liRssen  Peak,  Marysvilie,  Smartsvillc  Nevada 
City.  Pyramid  Peak,  Downieville.  Tr\ickee, 
Sonera  and  Big  Tree.  Others  are  in  i)reparatiou. 


.^ 


{"■lH'/f.'Ol:"/; 


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m 


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\ 


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r.  Sci  .  '1- 


352 


KEMP'S  ORE  DEPOSITS. 


lake  basin.  The  schists  are  seamed  by  dikes  of  porphj'ritic 
rock,  which  may  have  come  from  the  volcanic  center  of  Eed 
Mountain  or  from  other  volcanic  eminences  not  far  away. 
The  rock  from  the  central  and  south  peaks  of  Red  Mountain, 
when  examined  in  thin  sections  from  specimens  kindly  sent 
the  writer  by  H,  A.  Titcomb,  E.M.,  proved  to  be  hornblende- 
andesite,  but  the  dikes  from  the  vicinity  of  the  mines  were 
too  decomposed  for  recognition.  The  gold  ores  occur  in  quartz 
veins,  which  usually  are  in  association  with  the  porphyry 
dikes,  the  country  rock  being  the  mica  schist.  The  regidu 
suffers  for  lack  of  water,  but  as  it  is  now  connected  by  rail 
with  the  Santa  Fe  system,  a  number  of  mines  and  mills 
are  in  successful  operation.  The  accompanying  photograph 
(Fig,  i:5<i)  illustrates  the  country.'  The  remoteness  of  other 
camps  militates  against  their  development. 

2.r2.()l>.  On  the  eastern  border  of  California  and  lying  along 
the  eastern  slopes  of  the  Sierras  are  Inyo  and  Mono  counties, 
two  that  have  been  quite  serious  producers  of  silver  (with  suh- 
ordinate  gold)  in  past  years.  Deserted  or  greatly  dwindled 
mining  camps  are  frequently  met  throughout  the  mouutaius. 
The  region  lies  Avithin  the  confines  of  the  Great  Basin,  and  is 
somewhat  poorly  supplied  with  wa+er.  In  Inyo  County,  gran- 
ite, schists  and  crystalline  limestone  are  very  prominent  in  the 
general  geology,  and  the  ores  are  prevailingly  of  the  lead-silver 
variety,  and  in  limestone  walls.  The  Cerro  Gordo  and  Paua- 
mint    districts    were  heavy  producers    in  their  daj'.'"    JMono 

'  F.  M.  Endlich,  "Mining  in  the  Moh.'ive  Desert  of  California,'"  Eiin.  (uid 
Min.  Jour..   August   29,  1896,  147.     H.    G.    Hanks,  "On  the   Calico  Kis- 
trict."  FiiKiili  Rep.  ('al.  Sfcitr  Miiicnihvii.st.  1884.  :!()•>.    Win.  Irelan,  "On  the 
Calico  District.'  Ehjlith  fl  p.  Cal.  S(<(1f  Miiu'r(ih)(ii>>(,  ISSS,  4!» ).     W.  l.iiid 
gren.  "The  Silver  Klines  of  Calico  District.  California, "  Tniii.s.  Aiiici:  ///.••7 
^fill.  EiKj.,  XV..  TIT,     F.  L.  Nason.  "The  (lolcr  (fold  DigginL^s," /i,';*;/  ((/«/ 
Min.  Joitr..  March!*,  18!)'),  22;i     W.   A.   Skidniore.  "On  Calico  District.' 
Rep.  Director  of  the  Mint.  1884.  rm.     Rec.     Other  Reports  of  the  Director 
of  tlie  ^lint  and  Kaynioml's  earlier  rei)(>rts  niiiy  l»e  advaiitageunsly  cdii 
snlted.     In  the  ^fill.  iuhI  Sci.  /'/r.s.s-,  April  1.  1H!)<),  will   he  found  a  sketch 
of  the  Randshurg  district  and  of  the  Yellow  Aster  Jfine.     The  notes  in 
the  text  on  Raiidsburg  were  hascd  on  specimens  and  data  kindly  furinsluil 
by  the  writer's  friend.  II.  .\#  Titcond). 

"  11.  DeCroot,  "  IJeporton  Inyo  ( 'oiinty."  Tc»//*  Rep.  Cat.  State  Miiimiln 
gist,  1800.  2()!t.  W.  A.  Coodyear,  "Report  on  Inyo  County,"  Mf/// /A  My 
Cat.  State  Mincralogint.  1M88,  224-H09.     Ree.     H.    H.    Hanks,   "Silv.r  in 


Fl(i,  i;!0.  —  Vicir  of  h'linilshniy,  I'lilif..  lookiiKj  aoHthifcsf.     ,Scliists  iiiidrrlie 

iJic  ti)ini,  but  fJic  liills  arc  criijifirc.     From   a  photo- 

fjnilili  bji  H.  A.  Tilcoiiih.  E.  ^f. 


Flu.  i;5T.-  TItc  ati'Vi'iis  nii<lr<(iilic  ))l(ici  r  iiiiiif,  ^\iiro  Citi/,  Colorulo. 

From  a  j)liolo(jr(ijili. 


«t 


vm 


^m 


Fl«.  138. — View  in  tlio  Mulnkojf  Ifi/ib-diiJir  placer  mine,  North  Bluoinjidd, 
CaliJ'Drnid.      From,  a  photiuiraph. 


Fig.  131). — View  in  the.  Muhikoff  lljiilrmtiie  pUieer  mine,  North  Bluontjuld, 
L'uliJ'urniu.     From  a  pliutufjroph. 


THE  PACIFIC  SLOPE. 


353 


County  lies  next  north  of  Inyo,  and  is  remarkable  fur  the  vastc'e- 
vclopment  of  volcanic  rocks  that  it  contains.  While  there  are 
ijot  a  few  mining  districts  in  the  county  of  no  inconsiderable 
moment,  details  of  which  will  be  found  in  the  references  cited 
lelow,  yet  the  pre-eminent  one  is  Bodie.  At  Bodie  a  quite 
complex  series  of  veins  cut  hornblende-andesite,  over  which,  on 
the  surface,  is  volcanic  breccia.  Various  other  eruptives  occur 
ill  the  neighborhood.  The  faults  in  which  the  veins  are  found 
liave  been  formed  at  several  different  periods,  but  the  tracing 
of  their  exact  relations  will  require  very  careful  work.  The 
gangue  is  chiefly  quartz,  through  which  are  distributed  silver 
minerals  with  more  or  less  gold.*  Nearly  all  the  other  deep 
mines  for  the  precious  metals  in  California  yield  little  else  than 
gold,  and  although  a  few,  such  as  those  at  Ophir,  afford  con- 
yitlerable  silver,  they  will  be  mentioned  with  the  distinctively 
gold-quartz  veins. 

2.12.10.  Example  44.  Auriferous  Gravels.  (1)  River 
gravels,  or  placers  in  the  beds  of  running  streams.  These  have 
been  often  referred  to  in  other  States,  but  the  t^'pe  is  placed  in 
California,  as  they  are  there  best  known.  They  were  the  first 
gravels  washed  in  1841»,  and  although  substantially  exhausted 
by  18G0,  were  very  productive.  Eastward  from  the  great 
Sacramento  Yalle}-  the  surface  rises  with  a  quite  gentle  gradi- 
ent to  the  summit  of  the  Sierras.  The  country'  consists  chiefly 
of  metamorphic  rocks,  which  have  yielded  a  very  few  well- 
determined  fossils  of  both  Carboniferous  and  Jurassic  ages; 
but  the  identity  of  the  strata  in  all  the  area  is  difJicult 
t(i  make  out,  because  where  the  fossils  were  originally  present 
they  are  almost  entirely  destroyed  by   metamorphism.     Down 

(  alifornia,"  Fourth  Rep.  Cal  State  MiiierahxjLst,  1HS4,  iHn.  W.  A.  Skiil- 
iimre,  "Gold  and  Silver  Mining  in  California,  Past,  Present  and  Futiu-e," 
iiVp,  of  Director  of  the  Mint,  1884,  538. 

'  H.  DeGroot,  "  Eeport  on  Mono  Count}-, "  Tenth  Rej).  V<d.  State  Mineralo- 
gist, iHSiO,  336.  H.  W.  Fairbanks.  "Mineral  Depo.sits  of  Eastern  Califor- 
nia." .Imt/".  Geo!.,  March,  18%,  144.  "Notes  on  the  Geology  of  Eastern 
<  alifornia,"  Idem,  February,  185)6,  63;  describes  ^lono  and  Inyo  Counties. 
(  .  D.  Walcott,  "Lower  Cambrian  Rocks  in  Ea.stern  California,"  .l»(r/'. 
Jour.  Sei.,  February,  IS!).'),  141.  "Tiie  Appalachian  Type  of  Folding  in 
the  White  Mountain  Range  of  Inyo  County,  California,"  Idem,  March, 
l-".)*),  Kii).  H.  A.  Wliiting,  "Report  on  I\lono  County,"  Eiijhth  Rep.  Cat 
'•'I'tte  Mineralogist,  3r)2-4(>2.     "On  Bodie,"  383-402.     Rec. 


ff^ 


354 


h'KMP'S  out:  DEPOSITS. 


the  s«lopes  of  the  range  the  modern  streams  have  flowed  and 
cut  deep  canons  in  which  gravels  have  gathered.  Out  in  the 
more  open  country  the  gravels  have  also  accumulated  and  have 
furnished  some  productive  bars.  The  gold  has  been  derived 
piincipally  from  the  quartz  veins  of  the  slates,  which  are  later 
described,  and  has  been  mechanically  concentrated  in  the 
streams.  Before  coming  to  its  final  rest  it  may  have  lodged  in 
the  high  or  deep  gravels,  of  which  mention  will  next  be  made. 

It  is  accompanied  by  magnetite  as  a  general  thing,  by  zir- 
con, garnet,  and  rarely  by  other  heavy  metals,  such  as  j)lati- 
num  and  iridosmine.  The  greatest  amount  is  usually  near  tlie 
bedrock,  and  when  this  is  at  all  porous  the  gold  may  work 
into  it  to  a  small  distance  from  the  top.  The  gold  is  usually  in 
flattened  pellets  of  all  sizes,  from  the  finest  dust  to  nuggets  of 
considerable  weight,  which  show  evidence  of  being  water  worn. 
The  interesting  phenomena  connected  with  the  possible  circula- 
tion of  the  precious  metal  in  solution  through  the  gravels  are 
discussed  under  the  deep  gravels.  Important  deposits  of  the 
same  general  character  as  these  have  also  been  dug  over,  near 
Santa  Fe,  N.  M. ;  in  California  Gulch,  near  Leadville,  Colo. ; 
at  Fairplay,  Colo.;  in  San  Miguel  County,  Colorado;  in  the 
Sweetwater  district,  Wyoming;  near  Butte,  Mont.;  in  Last 
Chance  and  Prickly  Pear  gulches,  near  Helena,  Mont. ;  in  the 
Black  Hills;  in  southern  Idaho,  especiall}'  along  the  Snake 
River;  and  at  various  points  in  Washington  and  Oregon. 
Placers  of  this  type  have  also  been  found  on  the  slopes  of  the 
Green  Mountains  and  in  the  Southern  States,  but  they  never 
have  proved  of  serious  importance. 

2,12.11.  (3)  High  or  Deep  Gravels.  With  the  exhaustion  of 
the  river  gravels  the  gold  seekers  of  California  were  driven  to 
prospect  on  the  higher  slopes,  where  auriferous  gravels  much 
less  accessible  had  long  been  noted.  Increasing  observation 
and  development  have  shown  that  these  are  the  relics  of  former 
and  very  extensive  drainage  systems,  which  were  more  or  less 
parallel  with  the  present  streams,  but  of  greater  volume. 
The  beds  lie  in  deep  gulches  in  the  slates,  and  are  capped  in 
most  cases  by  basaltic  lava  flows  or  by  consolidated  volcanic 
tuflfs,  called  cement.  They  extend  some  ^oO  miles  along  the 
Sierras  and  up  to  7000  feet  above  the  sea.  They  have  at  times 
great  thickness,  reaching  GOO  feet  at  Columbia  Hill,  but  drop 


THE  PACIFIC  SLOPE. 


355 


elsewhere  to  1  or  2  feet.  Tbej-  vary  from  a  maximum  widtli  in 
workable  material  of  1,000  feet  to  a  minimum  of  150.  The 
inclosing  slates  on  the  sides  of  the  old  river  valley  are  called 
"the  rims,"  and  on  them  are  sometimes  found  other  gravels. 
In  some  districts  channels,  belonging  to  two  or  three  periods  of 
fl(jw,  have  been  traced.  They  tend  to  follow  the  softer  strata, 
breaking  at  times  across  the  harder  rocks.  The  channel  filling 
consists  of  gravi'l,  sand,  and  clays,  volcanic  tuffs,  and  firm 
basalt.  With  these  are  great  (juantities  of  silicified  trees,  and 
even  standing  trunks  project  through  some  beds.  The  gravel 
is  oftenest  formed  of  white  quartz  pebbles,  but  may  contain 
all  the  metamorphic  rocks  of  tbe  neigbliovbood,  and  even 
boulders  brought  from  a  great  distance.  The  gravel  at  times  is 
cemented  together  b}'  siliceous  and   calcareous  matter,  and  it 


Fio.  140. — Qenernlized  section  of  a  deep  f/rnvel  hod,  vith  technical  terms. 
After  R.  K.  Browne,  licp.  Vol.  Slide  Mineralof/M,  1890,  p.  437. 

then  requires  blasting ;  but  loose  gravel  also  occurs.  The  clays 
are  locallj'  called  "pipe  clays,"  and  are  o'  jn  interbedded  with 
sand  layers.  They  are  blue  when  unoxidized,  giving  rise  to 
the  term  "blue  lead,"  but  red  oxidized  clays  are  not  infre- 
quent. The  clays  contain  many  leaf  impressions  of  species 
thought  by  Lesquereux  to  be  late  Tertiary.  (See  further  under 
2.12.13.)  The  gravels  also  contain  bones  of  extinct  vertebrates, 
and  have  afforded  some  authentic  human  remains  and  stone 
implements  of  good  workmanship.  Tbe  volcanic  tuffs  have 
boeu  strong  factors  in  modifying  the  original  drainage  lines. 
Tliey  have  flowed  into  the  ancient  valleys  in  a  state  of  mud  and 
have  then  consolidated. 
2.12.12.     The  richest  gravels  are  those  nearest  the  bed  rock. 


366 


KEMPS  Olih'  DEPOSITS. 


In  these  the  distribution  of  the  gold  is  governed  more  or  les^.s 
by  the  character  of  the  ancient  channels.  It  favors  the  iusidos 
of  bends  and  the  tops  of  steeper  runs.  The  gradients  of  the  old 
channels  were  fairly  high,  often  running  100  to  200  feet  per 
mile.  Gold  has  also  been  found  by  assay  in  pyrite  that  has 
been  formed  in  the  gravels  since  their  deposition,  and  from 
this  it  is  evident  that  the  precious  metal  does  circulate  in  solu- 
tion with  sulphate  of  iron,  but  on  this  slender  foundation  some 
quite  unwarranted  chemical  hypotheses  for  the  origin  of  nug- 
gets have  been  based.  Substantially  all  the  gold  has  been  de- 
rived by  the  mechanical  degradation  of  the  quartz  veins  in  the 
slates  on  other  wall-rock. 

2.13.13.     The  depths  to  which  the  modern  streams  have  cut 


eooo 


5000 


«ooo 


3000 


2000 


2     3 


*     5      6    >      6      9     10     II     12     13    14    15    16     17    16     l»    20   21    i.    U  24-25  26  27 


mi  Iff 


Fig.  141. — Section  of  Forest  Hill  Diride,  PJarer  Count)/,  California,  to  illus- 

irate  the  relations  of  old  and  modern  lines  if  drainaye.     After 

li.  E.  Bniirne,  Rep.  Cnl.  State  Miueraloyist,  18i)0,  p.  444, 

out  their  channels  below  the  old  drainage  lines  have  received 
considerable  attention.  Whitney  concluded  that  no  disturli- 
ance  had  taken  place  siuce  the  old  gravels  were  laid  down,  but 
Le  Conte  has  inferred  that  there  has  been  a  tilting  or  elevation 
of  the  higher  parts  of  the  range,  all  moving  as  a  block.  Becker 
has  recently  described  in  the  high  portions  a  great  series  of  small 
north  and  south  faults  with  uniform  downthrow  on  the  western 
side  or  upthrow  on  the  eastern.  (See  paper  below,  cited  from 
Geological  Society  of  America.)  This  is  supposed  to  have  been 
of  varied  intensity  in  different  portions  and  to  have  been  limittl 
to  the  atrip  just  west  of  the  summit.  It  is  attributed  to  the  Pli(  >- 
cene  and  is  thought  to  have  increased  the  gradient  of  the  streams 
where  the  present  deep  canons  occur,  but  to  have  had  no  effe'  t 


THE  PACIFIC  SLOPK. 


867 


or  lesH 
insides 
the  old 
jet  per 
mt  has 
cl  from 
in  solu- 
m  solium 
A  nu{^- 
jeen  tle- 
iS  in  the 

lave  c\it 


received 
disturb- 
own,  but 
elevation 
Becker 
of  small 
western 
ted  from 
lave  been 
n  limitel 
the  Pli''- 
e  streams* 
no  effet  t 


near  the  plains,  where  the  old  and  new  channels  are  nearly  on 
the  same  level.  Later  work  has  cast  much  doubt  on  these  views. 
'Z.VZ.l^.  After  the  formation  of  the  deep  graveb  and  after 
the  volcanic  Hows,  glaciation  took  place  in  great  extent  over  the 
mountain  sides,  but  it  was  doubtless  later  in  tiniR  than  the 
glacial  period  of  the  East.  References  to  the  simil-fr  great  de- 
vtflopmeut  of  the  ice  in  Washington  have  already  been  made. 
Many  hypotheses  were  early  advanctnl  to  explain  the  deep 
gravels.  They  have  been  referred  to  llio  ocean,  to  ocean  cur- 
rents, and  to  glaciers;  but  it  is  now  well  established  that  they 
are  river  gravels,  formed  when  the  rainfall  was  probably  in 
excess  of  what  it  is  to-day,  and  when  the  attitude  of  the  land 
tuvvHrd  the  ocean  probably  was  different.' 

'  Q.  F.  Becker,  'Notes  on  tlie  Stratigniphy  of  Calif  )ruia,"  Bull.  Jl),  U. 
S.  (leol.  Sid'vei/.  "  Structure  of  tlie  Sierni  Xevadiis,"  (!<'<>}.  Soc.  ^\iiicr.,  II., 
4;i.  W.  p.  Blake,  'The  Various  Forms  in  wliich  (JoldOcicurs,"  Jicj).  Divce- 
fiir  of  the  Mint,  1884.  p.  573.  A.  J.  Bowie,  Jr.,  "Hydraulic  Mining  in  Cal- 
iluinia,"  Trans.  Amrr.  7»,s^  Mi'h.  Entj.,  VI.,  27.  R.  K.  Browne.  "The  An- 
cifiit  River  Beds  of  tiie  Forest  Mill  Divide,"  Rep.  iUtl.  State  Mineraloiji.st, 
181)0,  p.  435.  Rec.  "California  Placer  Ciold,"  Eii(f.  amlMiii.  Juttr.,  Fehiuary 
2,  1805,  101.  T.  Egleston,  "Formation  of  Gold  Nuggets  and  Placer  De- 
posits," Trans.  Ainer.  Inst,  ^fin.  Eikj.,  IX.,  Gil  "Working  Placer  Depos- 
its in  tlie  United  States,"  Seliuol  of  Mines  Qnartevlij,  VII.,  j).  101.  ,1.  11. 
lliinnnond.  "Auriferous  Gravels  of  California."  Rep.  Director  of  the  Mint, 
issi,  j).  610.  Rec.  Rep.  Cat.  State  Minerahxjist.  1889,  p.  105.  H.  Vt. 
JIanks,  "Placer  Gold,"  iir^J.  Direetor  of  the  Mint,  1882,  p.  ^28.  II.  G. 
Hanks,  William  Irelan  and  J.  J.  Crawford,  Rep.  Cal.  State  Mineralogist, 
Annual.  T.  S.  Hunt,  'On  a  Recent  Formation  of  Quartz,  and  on  Silici- 
iication  in  California," /iJxf/.  and  Min.  Jam:,  May  29,  1880,  ;5G9.  J.  Le- 
conte,  "The  Old  River  Beds  of  California."  Anwr.  Jonr.  Set.,  iii,,  XIX., 
8(1  p.  176.  J.  J.  McGillivray,  "The  Old  River  Beds  of  the  Sierra  Nevada  of 
California,"  Rep.  Direetor  of  the  Mint,  iss],  p.  (,;!().  R.  I.  Murchison, 
•  Sihu'ia,"  etc. ;  ccmtains  a  sketch  of  thedistrihutionof  gold  over  thee  .la. 
F.  L.  Nason,  "Tiie  Goler  Gold  Diggings,"  En(/.  and^Lin.  Jonr.,  'M  .en  9, 
1i^'l5,  223.  J.  S.  Newl)errv,  "On  the  CJenesis  and  Dislrihution  of  Gold." 
Sclinol  of  Mines  Qnarterli/.  Vol.  III.;  Eiaf.  (Utd  Min.  Jour..  December  24 
and  31,  1881.  J.  A.  Phillips,  "Notes  on  the  Chemical  Geology  of  the 
California  Gold  Fields."  Philo.'^.  Mag.,  Vol.  XXXVI..  ]).  321;  Proe.  Roi/. 
Si>e.,  XVI.,  394;  Anier.  Jour.  Sei.,  ii..  XI. VII.,  134.  F.  h.  Ransome,  "The 
fireat  Valley  of  California:  A  Criticism  of  Tso-;tasy," /?»//.  Dipt.  ofGeol., 
tw( ("a  o/Ca/.,  I.,  370-428,  189(5.  B.  Silliman,  -On  the  Deep  Placers  of 
the  South  and  Middle  Yuba,  Nevada  County,  California,"  Anwr.  Jour. 
Set.,  ii.,  XL. ,  1.  J.  D.  Whitney,  "  Aiuiferous  (Jravels  of  the  Sierras," 
Cambridge,  1880.  "Climatic  Changes  in  Later  Geological  Times,"  Cam- 
bridge.    See  also  references  on  succeeding  i)ages  relating  to  California. 


Ill 


858 


JihWfPS  OUH  Dh'l'OSrm 


a.  13. 15.     The  U.  S.  Geological  Survey  has   been  diroctiii}^ 
its  attention  in  recent  years  to  the  geolof^y  of  the  gold  l)elt  in 
the  Sierras  in  connection  with  the  issue  of  atlas  sheets,  based 
on  to})()graj)hic  and  geologic  surveys.      Several  of  these   are 
practically  conijjlete,  and  they  and  the  auxiliary  papers  which 
have  resulted  from  the  work  have  served  to  throw  a  flood  of 
light  upon  the  obscure  problems  of  the  geolog}'  of  the  Sierras. 
At  the  same  time,  as  cited  under  subsetiuent  paragraphs,  othor 
local  workers  have  been  active.     The  geological  rolations  of 
tho  gravels  as  well  as  the  solid  strata  have  been   made  clear  iu 
greater  detail  than  over  befoie,     Waldemar  Lindgren  has  dis- 
cussed the  geological  history  of  the  American  and  Yuba  rivers 
in  his  valuable  paper  entitled,  "Two  Neocene  Rivers  of  Cali- 
fornia" {Bull.   Geol.  Soc.  of  America,  IV.,  257,  mxi.)    Tiio 
conclusion  is  that  the  old  divide  in  general  coincided  with  the 
present  one,  but  that  the  slope  of  the  Sierra   has  been  consider- 
ably increased  since  the  time  when  the  Neocene  {i.e.,  Miocone 
and  Pliocene)  ante-volcanic  rivers  flowed  over  its  surface.     "It 
finally  appears  probable     .     .     .     that  the  surface  of  the  Sierra 
Nevada  has  been   deformed   during  this  uplift,  and  that  the 
most  noticeable  deformation  has  been  caused  by  a  subsidence  of 
the  portion  adjoining  the  great  valley,  relatively  to  tlie  middle 
part  of  the  range."     A  careful  review  of  the  age  of  the  aurifer- 
ous  gravels  in  general  by  Lindgren,  and  of  the  fossil   plants 
from  Independence  Hill,  by  Knowlton,  has  led  to  the  conclu- 
sion that  the  deep  gravels,  which  themselves  lack  fossils,  date, 
in  instances,  probably  as  far  back  as  the  Eocene,  but  not  earlier. 
Some  bench  gravels  certainly  were  strongly  developed  in  the 
Miocene  and  gravels  of  one  sort  or  another  have  been  formed 
from  that  time  to  the  present.^ 

Liudgien  has  even  brought  to  light  the  existence  of  an  aurif- 
erous conglomerate  in  the  upturned  Mariposa  beds  of  Jurassic 
age,  near  Mine  Hill,  Calaveras  County.  The  crushed  con- 
glomerate gave  good  colors,  bat  no  black  sand,  from  which  it 
was  inferred  with  great  reason  that  the  gold  came  from  veins 
already  existing  in  pre-Jurassic  time  in  the  earlier  strata  and 
before  the  intrusion  of  the  basic  igneous  rocks  of  the  region." 

'  W.  Lindgren,  "Age  of  the  Auriferous  Gravels  of  the  Sierra  Nevada," 
with  a  Report  on  the  Flora  of  Independence  Hill,  by  F.  H.  Knowlton, 
Jonr.  Gi'ol,  IV.,  881,  189(i. 

*  W.  Lindgren,  "  Auriferous  Conglomerate  of  Jurassic  Age  in  the  Sierra 
Nevada,"  Amer.  Jour.  ScL,  October,  1894,  275. 


Till-:  r.\cii'ic  s/jiPh'. 


So!) 


H.  W.  Fairbanks  has  controvorted  the  above  iuterpretatiou 
and  regards  tho  presonce  of  the  gold  as  due  to  hiter  niiueraliza- 
tion.' 

Fairbanks  also  takes  issue  with  the  interpretation  by  ]{.  L. 
Dunn  of  an  auriferous  conglomerate  in  tbo  Klamath  Moun- 
tains, as  a  river  gravel  of  pre-Chico  age,  regarding  it  rather  aa 
shore  conglomerate  in  the  Chico  itself.'* 

J.  S.  iJiller  has  discusf^ed  tho  early  physiograpby  but  for 
a  wider  range  of  country  than  any  of  the  (tapt>rs  hitherto 
cited.'  Mr.  Dillor  shows  that  the  western  side  of  tlie  present 
yierras  formed  in  the  Eocene  or  Tejcjn  times  a  gently-sloping 
base-level  of  erosion,  with  <]uiet  streams  and  extensive  super- 
ficial deposits  of  a  residual  character.  Tho  Sierras  wore  from 
1,000  to  7,000  feet  below  their  i)resent  altitude.  With  tlu^ 
^[iocetie  came  a  ])eriod  of  upheaval,  of  increased  gradients  and 
rapid  denudation  of  the  soft  surface  materials.  The  old  aurif- 
erous gravels  were  thus  formed  in  the  stream  channels  while 
the  lighter  materials  were  transjiorted  out  to  sea.  The  course 
of  development  is  graphically  traced  out  by  Diller  in  ac- 
cordance with  our  modern  knowledge  of  stream-erosion  and 
transportation.  For  southern  California,  A.  C.  Lawson  has 
described  a  somewhat  similar  development  in  later  geolog- 
ical time/  but  as  the  region  is  not  one  of  auriferous  gravels, 
it  is  only  cited  here  as  of  interesting  correlative  character.  H. 
W.  Turner  has  lately  reviewed  the  whole  stratigraphy  of  tho 
region  south  of  the  fortieth  parallel,  has  correlated  the  new 
formational  names  adopted  in  the  survey  atlas  sheets,  has 
added  many  valuable  notes  on  the  petrographj'  of  the  igneous 
rocks,  and  has  outlined  the  stratigraphical  relations  of  the 
gravels.°  Mr.  Turner  distinguishes  two  series  of  Neocene 
river  gravels     (p.   JUl).       (1)    The   older    gravels    composed 


'  II.  W.  Fairbanks,  "  Auriferous  Conglomerate  in  California,"  Eng.  and 
Min.  Jour.,  AprilST,  1895,  ;J89. 

»  R.  L.  Dunn,  TiirJfth  Ami.  Rrp.  fal  State  nriiicralngist.  ISfll,  459. 

"  J.  S.  Diller,  "Revolution  in  tiie  Toi)of;rai)hy  of  tlio  Pacific  Coast  since 
the  Auriferous  Gravel  Pevio<i,"  Jour.  Geol.,  II.,  83,  1H!)4. 

'A.  C.  Lawson,  "The  Post  Pliocene  Diastrophisni  of  the  Coast  of 
Southern  California,"  Bull.  Dcpt  of  GcoL,  Univ.  of  Cat,  I.,  115,  Decem- 
ber. 1893. 

'  I ..     . .  Turner,  ««(,e.yi.ogicul  iNotes  on  the  bierra Nevada,"  Amer.  Geol., 
XIII.,  pp.  238,  297,  1894. 


in  the  Sierra 


3G0 


KKMP'S  CUM  DKI'OSITS. 


Iliiii 


cbieHyof  whito  quartz  jwliblos  and  fro(juently  capped  by  rbyo- 
litie  flows.  Tbese  may  bo  cbaraoterizod  iu  a  Inoiid  way  antbo 
gravels  formed  boforo  tliovolcanio  period.  (".')  A  later  neritis, 
coiitaiiiiii;^  volcaJiic;  jJohblfH  cbicMy  of  andesite  and  later  in  a^^e 
tban  tbo  rby(jlitie  flows.  Tiiese  may  be  called  the  gravels  of 
the  volcanic  period.  Such  gravels  are  often  ca])p»Ml  by  audesite- 
tutTs.  Inchided  fossil  leaves  indicat«^  that  the  <  Ider  gravels  are 
IMiocene  or  Eocene;  the  later,  PlioctMie.  The  Pliocene  rivci 
gravels  merge  into  shore  gravels  of  the  same  age  in  Amador  and 
Calaveras  counties.  The  pebbles  in  the  shore  gravels  are  i 
ite,  mica-schist,  (inartz-porphyrite,  granitoid  rocks,  ani  te, 
and  rhyolite,  the  last  named  being  at  times  very  abundant  and 
characteristic.  They  appear  to  have  boon  deposited  along  tlio 
shores  of  the  great  gulf  which  filled  the  central  valley  of  Cali- 
fornia in  these  times.  They  now  range  as  a  general  thing  "lOO 
to  "tW  feet  above  the  sea.  Later  than  the  Pliocene  gravels  are 
the  Pleistocene,  both  shore  and  river  deposits.  The  former 
occur  in  the  dejjressions  between  the  Neocene  and  older  billH 
and  at  a  lower  altitude,  by  one  to  several  hundred  feet.  Tliey 
seem  to  consist  of  the  harder  pebbles  of  the  Pliocene  gravels, 
the  softer  ones  having  been  destroyed  by  abrasion.  The  Pleis- 
tocene river  gravels  lie  usually  less  than  loo  feet  above  tlie 
present  streams,  and  also  in  remnants  of  tl:o  channels  '  be- 
hind by  old  changes  of  course.  They  and  the  shore  de^  of 
this  time  are  often  highly  auriferous.  Several  lake-bottons  of 
this  period  have  been  recognized  where,  for  some  reason,  sudi 
as  the  damming  of  a  stream  by  a  volcanic  flow,  or  a  probahlo 
mountain  upheaval,  the  waters  were  set  back.  Theso  lakrs 
have  left  benches  which  mark  their  old  shore  lines.  Finall> . 
we  have  the  recent  stream  gravels  and  alluvium.  These  papers 
show  that  the  geological  relations  are  more  complex  than  was 
earlier  known,  but  in  their  practical  bearings  the  gravels  can 
perhaps  hardly  be  better  grouped  than  into  the  River  gravels 
or  placers,  in  the  beds  of  running  streams,  and  the  High  ei* 
Deep  gravels,  according  to  the  old  nomenclature. 

2.12.1G.  In  resume  of  the  above  review  it  should  be  first 
appreciated  that  stream  gravels  are  the  least  favorable  of  all 
sediments  to  the  preservation  of  organic  remains.  Not  only 
are  few  animals  with  hard  parts  resident  of  swiftly  tlowiutf 
currents,  but  such  shells  or  bones  as  might  reach  them   woiiKl 


TIIK  rACIFIC  SLOPE. 


301 


m 


j?  rhyo 
y  iiHtlit^ 
r  Herit's, 
r  in  ii^y 

JlV(?lS  of 

udoHitc- 

iVels  HVB 

Qe  rivci 
idor  ami 
ec 

!in>       i«, 
(liiut  Hud 

f  of  Cali- 
tliiuf^  ^'*H) 
i-iivt>ls  are 
u>  fornitT 
jUltn-  hills 
et.     They 
)  gravels, 
rho  rieis- 
ahovo  the 
H  '       he- 
e^  of 

bottoiud  of 
i^S(^u,  such 
I  prohahle 
lesii  hiki's 
Finally. 

ICHO  l)allt■l'^ 

cthan  was 
ravels  can 
■r  gravels 
Hi^'h  o\- 

111  be  fii'H^' 
able  of  all 

Not  only 

\y   tlowini? 
lem   WOuUl 


lio  liable  to  destructlou  from  the  trituration  of  the  houldorH. 
The  Htratigraphical  rolatious  of  the  gravida  must  th(>n«foro  he 
worked  out  in  groat  part,  by  other  forms  of  evidence.  It 
sliouhl  also  be  appreciated  tliat  the  old  channtd-til lings  remain 
to  us  to-day  only  as  fragments  of  their  former  extent,  and  that 
they  are  largely  buried  under  lava  Hows  and  tuffs.  The 
gravels  therefore  appear  in  narrow  outcrops  and  set  up  narrow 
valleys,  which  are  cutoff  from  their  neighbors,  north  and  south 
hy  high  divides.  While  thoj'  were  being  deposited,  moreover, 
ill  past  geological  time,  more  extensive  contemporaneous  forma- 
tions were  being  laid  down  in  the  then  submerged  valley  of 
California,  and  with  the  latter  it  is  important  to  correlate  them. 
Tlio  kinds  of  evidence  that  are  available  are  the  following :  The 
1  it liological  character  of  the  pebbles;  the  relations  of  the  non- 
iHSHiliferous  gravels  to  others  in  whose  interhedded  clays  or 
tuffs,  fossil  plants  occur;  thf  i)hysiogra})hic  conditions  under 
Avliich  the  gravels  were  laid  down,  and  which  must  have  been 
uniform  over  a  gre'\t  part  of  the  State  and  liave  left  correlative 
records,  if  they  can  be  found ;  and  finall)'  the  relations  of  the 
gravels  to  the  volcanic  outbreaks,  whose  lithological  succession 
may  be  worked  out. 

In  the  following  tabular  statement  the  endeavor  has  been 
made  to  utilize  the  classification  of  the  gravels  into  periods, 
which  was  prepared  by  Koss  K  Browne  {l<>tli  Ann.  Rvp.  (Uilif. 
Shite  Minendogifit,  4:57)  and  Id  thereto  other  determinations 
h\-  the  geologists  of  the  U.  S.  Sur  v,  or  by  California  geologists. 
Jniassic.  Aurihrous    gravel,    now  a    con- 

glomerate. ' 
Cretaceous.  Pre-Chico  auriferous  river  gravel 

in   the    Klamath    Valle}',    Siskiyou 
County.*        (They     may    be  beach 
gravels  of  the  Chico  itself.)' 
Eocene.  Auriferous  gravels  doubtful. 

Jliocene.  Deep  gravels  with  quartz   pebbles 

of  Browne's  First  Period,^  which  was 

'  W.  Liudgren,  "An  Auriferous  Cimglouiorate  of  Jurassii;  Age  from  the 
Sierra  Nevada,"  Ainer.  Jour.  Sci.,  October,  1894,  275;  see  also  H.  W.  P'air- 
b.iiiks,  Eiig.  and  Min   .Jour..  \\ni\  27,  1S9.-),  :}S!l 

'  R.  L.  Dunu,  "Auriferous  Coiigionierate  in  California."  Ticdfili  Ann. 
l\ip.  Cal.  State  Mineralogist,  1894,  459;  see  also  H.  W.  Fairbanks,  as 
uti'lcr  preceding  reference. 

Moss  E.  Browne,  "Tiie  Ancient  liiver  Reds  of  the  Forest  Hill  Divide," 
Ta.thAnn.  Rep.  Cal.  State  Mineralo(ji.^t,  1890,  487-440. 


m^i 


KEMPS  ORE  DEPOSITS. 


closed  by  Pliocene  andesite  enip- 
tious.  The  chief  auriferous  gravels 
belong  in  this  period.  Bench  gravels. 
Some  rhyolite  eruptions  occurred 
during  it/  (Turner's  "Intermedi- 
ate Period,'"  pebbles  of  pre-Creta- 
ceous  sedimentary  and  igneous  rocks; 
presumably  latpv  than  the  iirHt 
period,  but  of  uncertain  taxonomic 
relations  with  the  second  period.)' 
Miocene  Second  Period  of  Browne'  gravels 

Pliocene.  formed  in  shifting  chauiiels  during 

or  between  successive  volcanic  erup- 
tions and  mud  flows,  both  of  andesitic 
nature.     Pebbles  mostly  vulcanic. 
Pliocene  to  Third    Period  of  Browne,*  dating 

Present.  from  last  important  lava  and  mud- 

flow;  beginning  and  completion  of 
present  stream  valleys.  River 
gravels. 

2.13.17.  Example  45.  Gold  Quartz  Veins.  Veins  of  gold- 
bearing  quartz,  often  described  as  segregated  veins,  in  slates  or 
metamorphosed  igneous  rocks,  and  more  or  less  parallel  \\\i\\ 
the  schistosity.  Less  commonly  the  walls  are  massive,  igneous 
rocks.  The  quartz  contains  auriferous  jiyrite,  free  gold, 
arsenopyrite,  chalcopyrite,  tetrahedrite,  galena,  and  blende, 
but  pyrites  is  far  the  most  abundant.  Tellurides  have  been 
occasionally  detected  in  small  amounts.*  Tlie  veins  approxi- 
mate at  times  a  lenticular  shape,  which  is  less  marked  iu  Cal- 
ifornia than  iu  some  other  regions,  and  which  shows  analogies 
of  shape  with  pyrites  lenses  (Example  in)  and  magnetite  lenses 

'  H.  W.  Tunier,  "Auriferous  Gravels  of  the  Sierra  Nevada,"  Amer. 
Geol,  June,  1895,  ;}72. 

"  IJiulgren  and  Knowlton,  "  Age  of  the  Auriferous  Gravels  of  the  SitMra 
Nevada."  Jour.  Qcol,  IV.,  881,  180(};  see  esi)eeially  table,  p.  !)06. 

^  Ross  E.  Browne,  "The  Ancient  River  Beds  of  the  Forest  Hill  Divide," 
Tenth  Ann.  Rvp.  Col.  State  MineraJogisf.  1890,  437-140. 

Each  of  the  above  ^Kipers  has  important  complenieutary  relations  to  tlie 
others. 

*  For  a  rpview  and  bibliograi>hy  of  the  Tellurides,  see  J.  F.  Keni]i,  The. 
Mineral  Inxlufilry,  Vol.  VI.,  p.  295. 


esite  ernp- 
nm  gravels 
ich  gravels. 
3  occurrt>(l 
'lutermedi- 

pre-Creta- 
leous  rocks ; 
1    the     lirst 

taxonomic 
period.)"' 
ne^  gravels 
lela  during 
icanic  enip- 
of  andesitic 
volcanic, 
nie,*  dating 
a  and  nnul- 
mpletion  of 
'8.        River 


'ins  of  <>;()ld- 

in  slates  (jr 

irallel  witli 

ive,  igneous 

free  gold, 

and  blende, 

Lave  l)eeii 

ns  approxi- 

rked  iu  Cal- 

V8  analogies 

aetite  lenses 


vada,"  Aiiiii: 

i  of  the  Sierra 

1106. 

;  Hill  Divide," 


ilations  to  the 
F.  Kemp,  Tin- 


~  < 


>   A 


3 


=    55 


■-    y 


)   \   s 


0 


r^A'  PACIFIC  SLOPE. 


303 


(Example  1:J).  In  such  cases  the  fissure- vein  character  is 
HGinewhat  obscure.  In  California  the  veins  occupy  undoubted 
fissures  in  the  slates.  The  largest  and  best  known  is  the  so- 
called  Mother  Lode,  which  is  a  lineal  succession  of  innumerable 
larger  and  smaller  (juartz  veins  that  run  ]iarallel  with  the  strike, 
and  rarely  cut  the  steep  dip  of  the  slates  at  an  angle  of  1()°.  It 
was  doubtless  formed  by  faulting  in  steeply  dipping  strata.  The 
wall  rocks  of  the  California  veins  embrace  many  types  of  igneous 
rocks,  as  well  as  sedimentary  slates,  for  all  these  enter  into  the 
Avestern  slopes  of  the  Sierras.  The  frequent  serpentine  is  prob- 
ably a  metamorphosed  igneous  rock,  wh^'^  the  diabase  and 
diorite  form  great  dikes.  Considerable  calcite,  dolomite,  and 
Hukerite  occur  with  the  quart/,  and  very  often  it  is  penetrated 
by  seams  of  a  green,  chloritic  silicate,  which  was  provisionally 
called  mariposite,  but  which  has  been  shown  by  Turner  to  be  a 
potassium  mica,  colored  green  by  chromium.  The  quartz 
veins  vary  somewhat  in  appearance,  being  a*  times  milk 
white  and  massive  (locally  called  "hungry,"  from 
its  general  barrenness),  at  times  ,  greasy  and  darker, 
and  again  manifesting  other  differences,  which  are 
difficult  to  describe,  although  more  or  less  evident  in  speci- 
mens. The  richer  quartz  in  many  mines  is  somewhat  banded, 
and  is  called  ribbon  quartz.  The  quartz  has  been  studied  in 
thin  sections,  especially  in  rich  specimens,  by  W.  M.  Courtis, 
who  shows  that  fluid  or  gaseous  inclusions  of  what  is  probably 
carbonic  acid  are  abundant.  In  rich  specimens  the  cavities  tend 
to  be  more  numerous  than  in  poor,  but  more  data  are  needed  to 
form  the  basis  of  any  reliable  deductions.  Some  quartz  shows 
evidence  of  dynamic  disturbances.  The  walls  of  the  veins  are 
themselves  at  times  impregnated  with  the  precious  metal  and 
the  attendant  sulphides.  The  rich  portions  of  the  veins  occur 
in  chutes  which  run  diagonally  down  on  the  dip. 

;2.13.18.  The  great  Mother  Lode  is  the  largest  group  of 
veins  in  California.  It  extends  112  miles  in  a  general  north- 
west direction.  Beginning  in  Mariposa  Count}-,  in  the  south, 
it  crosses  Tuolumne,  Calaveras,  Amador,  and  El  Dorado  coun- 
ties in  succession.  It  is  not  strictly  continuous  nor  is  it  one 
.single  lode,  but  rather  a  succession  of  related  ones,  which 
tnanch,  pinch  out,  run  off  in  stringers,  and  are  thus  complex 
in  their  general  groiiping.     Over  500  patented  locations  have 


364 


KEMP'S  ORE  DEPOSITS. 


been  made  on  it.  Whitney  suggested  that  it  may  have  origi- 
nated from  the  silicification  of  beds  of  dolomite,  but  others  re- 
gard it,  with  greater  reason,  as  a  great  series  of  veins  along  a 

Surface 


Surface 


Sctla 
200      lino 


400       600  Ft. 


Figs.  143  and  144. — Ore  shoots  of  Nevada  City  and  Orass  Valky  mines,  <al. 
After  W.  Liiuhircn,  XV 11.  Ann.  h'lp.  U.  S.  Geol.  Survey, 
Part  II.,  Plate  XVIII.,  slightly  reduced. 

fissured  strip.  The  veins  are  often  left  in  strong  relief  by  the 
erosion  of  the  wall  rock,  and  thiis  are  called  ledges,  or  rec^fs. 
Some  discussion  has  arisen  over  the  condition  of  the  gold   in 


THE  PACIFIC  iSLOPE. 


365 


the  pyrite,  but  in  most  cases  it  is  the  native  metal  mechanically 
mixed,  and  not  an  isomorphons  sulphide.  It  has  been  detected 
ill  the  metallic  state  in  a  thin  section  of  a  pyrite  crystal  from 
Dnuglass  Island,  Alaska,  as  later  set  forth  {'-i.l'-i.V'i,)  and  the 
fact  that  it  remains  as  the  metal  when  the  pyrite  is  dissolved 
in  nitric  acid  makes  this  undoubtedly  the  general  condition. 
The  association  of  gold  with  bismuth,  which  has  been  shown 
by  R.  Pearce  to  occur  in  the  sulphurets  of  Gilpin  County, 
Colorado  (referred  to  on  p.  ;30()),  and  the  difficulty  experi- 
enced in  amalgamating  some  ores,  indicate  the  possibility  of 


Fig.  lio. — Section  of  the  Pittsburg  vein,  ninth  level,  Nevada  City  district, 

Cal.     XVIL  Ann.  Rep.  IT.  S.  Geol.  Survey,  Part  II.,  p.  304, 

reduced  one  half. 

other  combinations.  When  crystallized,  gold  has  shown,  in 
oiip  specimen  and  another,  neaT-ly  all  the  bolohedral  forms  of 
tile  isometric  system,  but  the  octahedron  and  rhombic  dode- 
caliodron  are  commonest. 

■'.13.19.  The  veins  are  younger  than  the  igneous  rocks  with 
wliieh  thej^are  associated.  Granite  and  grano-diorite  are  espe- 
cially frequent,  but  diorite,  gabbro,  diabase,  porphyrite  and 
serpentine,  presumably  derived  from  Sv.-">e  basic  intrusion,  are 
al<o  met.  Although  Von  Richthofen  stated  that  the  ■•  eins  sel- 
dom occur  far  from  granite,  this  has  been  shown  by  Liudgrento 


366 


KEMPS  Olih'  DKrOSlTS. 


\ 


be  unjustified.  The  greater  number  are  in  slates,  antl  the 
richest  in  a  particular  series  of  slates,  but  they  also  cut  all  mau- 
ner  of  igneous  rocks  and  have  no  constancy  of  directiun.     No 


SECTION  D-B 


:■•^^•^^^•.••  ••••■••.••■.•■.•.••.  ■•.v.^^jj^u   \\,    v  \^ A     ■  ■  "■    \\i 


Fia.  140. — Q('olof)ic((l  section  at  the  Mervifithl  rein;  Providence  claim,  Nernda 

City  district,  Cat.     After  W.  I.indgren,  XVII.  Ann.  Rep.  U.  S.  Ocol. 

Survey,  Part  II.,  Plate  XXL,  ulie/htly  reduced, 

sharp  line  divides  them  from  silver-gold  veins,  which  occasion- 
ally occur  in  the  distinctive  gold -belt  nor  from  the  veins  earlier 


Fio.  147. — Cross. section  of  vein  in  St.  John  mine,  fifth  level,  Nevada  City  dis- 
trict, Cal.     After  W.  Lindgren,  XVII.  Ann.  Rep.  U.  8. 
Oeol.  Survey,  Part  II.,  p.  223, 

described  in  eastern  California  (2.12.07),  but  still  the  gold- 
(piartz  type  is  in  characteristic  examples  sufficiently  pronounnnl 
to  justify  its  special  treatment.     The  close  relationships  that 


THE  PACIFIO  SLOPE. 


367 


prevail  between  pegmatite  diites  or  veins,  at  one  extreme  and 
(juartz  veins  at  tlie  other,  in  many  parts  of  tbe  world,  and  the 
occasional  auriferous  character  of  true  pegmatites,  may  be  sug- 
gestive as  throwing  light  on  their  nature  and  origin,  especially 
in  regions  of  intrusive  granite. 

While  igneous  dikes  often  form  one  wall  and  slate  the  other, 
the  source  of  the  ore  has  been  placed  by  our  best  observers  in 
(locp-seated  regions,  whence  the  uprising  solutions  have  brought 
it.  Lateral  secretion  finds  slight  support  and  the  character  of 
the  walls  has  exercised  small  influence,  yet  the  presence  of  igne- 
ous rocks  is  in  the   large   way  favorable,  because  iiidicating 


,  V  '\Soft-ChloriHc~Jl()dk 


Fio.  148. — Cross-section  of  the  Maryland  vein,  in  dopes  above  the  ir^OO-foot 

level,  Grass  Valley  district,  Gal.     After  W.  Lindgren,  XVII. 

Ann.  Rep.  U.  8.  Geol.  Survey,  Part  IL,  p.  226, 

slightly  reduced. 

thermal  conditions  at  depths,  which  have  stimulated  mineral- 
beat  ing  circulations, 

Fairbanks  has  thought  that  evidence  of  the  replacement  of  the 
wall  rocks  could  be  noted,  but  Lindgren  controverts  this  view 
and  refers  them  to  the  filling  of  actual  cavities.  As  a  rule, 
they  are  not  much  broader  than  two  or  three  feet,  although  a 
network  of  small  veins  and  even  solid  quartz  may  extend  over 
a  niiK'h  greater  width,  and  the  gold  may  to  a  considerable  de- 
gree impregnate  the  wall-rock.  In  the  case  of  a  considerable 
width  of  pure  quartz,  say  20  or  30  feet,  an  original  cavity  of 
this  size  is  thought  improbable  by  Fairbanks,  who  cites  such 


.^ 


piHTT^ 


388 


KEMP'8  ORE  Vh'POSITS. 


veins  as  strong  indications  of  replacement.  Tliat  some  gold- 
bearing  ore  bodies,  which  depart  from  the  typical  quartz  vciu, 
have  been  deposited  by  replacement  is  also  maintained  by  H. 
W.Turner*  who  mentions  the  Diadem  lode,  southwest  of  Meadow 
Valley,  Plumas  County,  which  appears  to  be  a  bed  of  linicHtoiie 
or  dolomite  chiefly  replaced  by  gold-bearing  (jnartz  and  chal- 
cedony, but  in  such  a  way  that  fossil  foraminifera  are  still 
identifiable  in  the  ore.  Turner  also  mentions  a  number  of  alliitic 
dikes,  of  which  one  at  the  Shaw  mine  is  described  in  the  next 
paragraph,  and  which  are  impregnated  with  gold-bearing  pyrites 


Fig.  149. — Crosii.sectionoftlie  Brvnsmck  vein,  on  the  IQO-foot  level,  Grass 

Valley  district,  Cal.     After  W.  I.iiuhjren,  XVII.  Ann.  Rep. 

U.  -S.  Geol.  Survey,  Part  II.,  p.  230. 


of  low  grade.  The  latter  has  partly  entered  cracks  and  partly 
impregnated  the  rock  itself.  In  connection  with  replacenn^ut, 
however,  Lindgreu  has  acutely  remarked  that  siliceous  replace- 
ments exhibit  either  a  very  fine-grained  aggregate  of  minute 
quartz  crystals  or  else  chalcedony,  both  (juite  different  from  the 
coarsely  crystalline  quartz  of  the  typical  veins. 

2.13.20.  In  rare  instances  the  gold  is  associated  with  some 
other  gangue  than  quartz.  Thus  in  Vol.  XIII.,  p.  24,  of  the 
Tenth  Census,  G.  F.  Becker  records  gold  in  calcite,  in  the 
Mad  Ox  mine  of  Shasta  County,  where  the  hanging  Avail  is  a 

*  H.  W.  Turner,  "  Replacement  Ore  Deposits  in  the  Sierras,"  Joiir.  u<'ol., 
May-June,  1899,  S?89. 


'I 


TUE  VACIFKJ  ISLOPE. 


301) 


siliceous  limestone.  J.  S.  Diller  has  cited  a  similar  case  from 
Miners ville,  Trinity  County.  The  gold  occurred  in  veiulets  of 
calcite  in  u  dark,  carbonaceous  shale  {Atner.  Jour.  Hci.,  Feb- 
niar)',  ISDO,  p,  KiO).  Waldeniar  Lindgren'has  described  an  in- 
stance in  which  gold  with  some  silver  occurred  in  seams  of  barite, 
which  were  themselves  in  a  kaolinized  zone  in  diabase  and  dia- 
base-porphyrite.  In  the  kaolin  ().34*?6  BaSOi  was  determined 
by  analysis.  It  may  have  been  derived  from  the  feldspar  of 
the  original  diabase.  W,  F.  Hillebrand'  has  lately  shown 
tlio  wide  distribution  of  both  barium  and  strontium.  Liud- 
gren''  has  also  written  of  most  remarkable  veins  at  Meadow 
Lake  in  Nevada  County,  that  contaiu  auriferous  sulphides  and 
arsenides  in  a  gangue  of  tourmaline,  (juartz  and  ejjidote  in 
giauitic  and  dialjasic  rocks.  Tliis  aggregate  suggests  fuma- 
rolic  action.  Siniilarassociationsof  gold  with  tourmalino  have 
been  met  in  the  Zoutpansberg  District,  South  Africa,  and  in 
Brazil,  as  earlier  noted.  Through  the  kindness  of  Mr.  Leo 
vuii  Rosenberg,  the  writer  has  had  an  opportunty  to  examine 
a  suite  of  ores  from  the  Shaw  mine,  El  Dorado  County,  which 
have  been  donated  to  the  School  of  Mines,  Columbia  Univers- 
ity. The  same  had  been  previously  studied  by  H.  W. 
Turner,  of  the  U.  S.  Geol.  Survey,  by  whom  the  determina- 
tions were  originally  made.  The  mine  is  based  on  a  dike  of 
porphyrite,  sixty  or  seventy  feet  thick  and  charged  with 
pyrites.  It  is  auriferous  throughout,  but  richest  next  the  walls. 
Tlie  gold  in  the  native  form  occurs  in  vein  lets  of  albite,  which 
ramify  through  the  porphyrite.  An  analysis  by  Mr.  Hille- 
brand      established    the     identity     of    the     albite.*      T.    A. 

'  VV.  Liixlgren,  "The  Gold  Deposit  at  Pine  Hill,  Califoi'nia,"  Amer. 
.Jour.  Sci.,  August.  1S92,  p.  91. 

•  \V.  F.  Hilk'hmiHl,  "Tlie  Widespread  Occurrence  of  Barium  and  Stron- 
tium in  Kociks,"  Join:  Aiiiei:  Cliciii.  Soc,  February,  IbliM,  p.  SI. 

'  W.  Liudgren,  "The  Auriferous  Veins  at  Meadow  Lake,  California," 
Ainii:  Jour.  Sei.,  September,  ISO:!,  201. 

*  Since  the  above  was  written  ]\lr.  Tiu'uer  has  ])ublis)ie(l  the  residts  of 
Ills  examination  of  tliis  ore,  as  well  as  many  addit  ional  ini|)ortant  lujtes  on 
tlie  associates  of  the  gold.  (H.  W.  Turner,  "Notes  on  the  Gold  Ores  of 
California,"  Avier.  Jotir.  So'..  .Tune,  18i)4.  p.  4fi7. )  Mr.  Tiu-ner  also  cites 
gold  ill  (piartz  in  rhyolite,  and  gold  with  cinnabar.  For  a  cross  section 
of  the  mine,  see  E.  E.  Olcott,  Trans.  Amer.  Inst.  Min.  En<j.,  XXIV.,  SK). 
Oth(»r  notes  appear  in  a  jxiper  by  C.  A.  Aaron,  Eng.  and  Miii.  Jonr.,  Jso- 
voaiber  19,  1892,  and  in  a  paper  in  the  Amer.  Geol.,  XVII.,  y«'\  189(5. 


870 


AKMP'S  Olth'  J)h'I>0.sj'J\s. 


\ 


Rickard'  has  called  attention  to  the  especial  abuiidauce  of  ^uUl 
at  the  iutersection  of  anmll  (iiiartz  veins  in  Tuolumne  and  (  al- 
averas  counties,  California,  and  to  the  (X'currence  of  a  particu- 
larly rich  pocket  in  the  Hathgcb  mine,  San  Andreas,  wlnro  a 
small  vein  was  faulted  a  i"(!w  iuchos,  and  where  the  gold  was 
associated  with  ])itcli-l)lende  or  urauiuite  and  uranium  ochre.'- 
W.  11.  Storms  describes  the  Alvord  mine  in  San  Bernardino 
County  where  the  gold  occurs  with  a  siliceous  limouite  in 
chutes  in  a  belt  of  limestone."'  Storms  in  tlio  citations  given 
below  records  a  great  variety  of  wall  rocks  in  which  the  veins 
occur,  as  well  as  interesting  mineralogicai  details. 

a.l2.:il.  The  formation  of  nuich  the  greater  number  of  the 
veins  followed  the  intrusion  of  the  grano-diorite,  which  oc- 
curred at  the  close  of  the  Jurassic  or  in  early  Cretaceous  time. 
Some,  however,  may  have  existed  before  this,  as  is  shown  by 
Lindgreu's  interpretation  of  the  Jurassic,  auriferous  conglomer- 
ate, earlier  cited,  and  a  great  series  of  veins  certainly  followed 
the  Tertiary  igneous  outbreaks  in  tlio  high  Sierras.  It  seems 
(juite  indisputable,  as  advocated  by  Liudgren,  that  the  gold 
and  its  associated  minerals,  including  the  oimrtz  gangue  canic 
up  in  heated  alkaline  solution,  and  that  the  vein  formation 
was  attended  by  extended  carbonatization  of  the  walls.  Tlir 
deposition  of  the  silica  had  slight  chemical  effect  on  the  wall 
rock  in  other  respects,  for  the  change  of  the  latter  to  carbonates 
is  the  chief  alteration  visible.  The  enormous  introduction  of 
silica  is  one  of  the  nmst  extraordinary  features  of  the  geology 
of  the  Sierras,  and  indicates  a  remarkable  activity  of  circulat- 
ing waters. 

The  igneous  intrusions  doubtless  promoted,  if  they  did  not 
cause,  the  circulations.*    While  the  gold  is  often  entangled  iu 


•T. -A.    Rickard,    "Certain  Dissimilar    Occurrences    of    Gokl-beariii},' 
Quart/,"  Proc.  Colo.  Sci.  Soc.,  Septeiuher,  ISiCJ,  ]>]).  (i-!). 

^  Henry  Lewis  lias  f^iven  a  very  c()inj)lete  review  of  the  associates  ainl 
occurrence  of  gold  in  the  Miiierdlofjical  M<i(f.,  X.,  241,  London,  189;{. 

'  W.  H.  Storms.  "The  Wall  Rocks  of  California  Gold  Jlines,"  Eng.  ami 
Min.  Jour.,  February  y;5,  IH!).'),  172. 

*  V.  Alger,  "  Cry.stallized  Cold  from  California,"  ^Imcr.  Jbrm /Sc^,  ii  . 
X.,  lOL  jr.  Attwood,  "On  the  Wall  Rocks  of  California  Gold  Quartz  and 
the  Source  of  the  fJold."  Rep.  Col.  State  M'nivrahxjiHt.  18KS,  p.  771  (thoiiulit 
to  he  due  to  igneous  injection  in  ilia.biLse).  W.  V.  Blake.  "  On  the  I'ar 
allelism   between  the  Deiwsits   of  Auriferous  Drift  of  the  Appalachian 


Tllh:  PACIFIC  tiLoPE. 


371 


e  of  ^nUl 
mul   (  al- 
i  iJiirtirii- 
,  wboro  a 
gold  was 
11  ochrt'.'" 
eriiardiuo 
lumito  in 
J118  given 
the  veins 

iber  of  the 
which  oc- 
;eous  time. 

shown  by 
2onglonier- 
y  foUowetl 
It  seems 
it  the  giild 
iiigiie  oaiiic 

format  i<  111 

ills.     The 
the  wall 

carbonates 
eduction  (if 

le  geology 
of  ciiculat- 

ley  did  not 
itangled  iu 


u 


lold-beariiif; 


issociates  and 
es,"  £"(/•  '""' 

7()»r  Sci.-  ii  ■ 
\d  Quartz  and 

171  (Ihouulit 
"Ontlu"  r.ii- 

Appalai-liiau 


jiyrite,  and  while  it  appears  to  liave  been  associated   with  this 
ir*)n  compoimd  iu  its  precipitation,  yet  it  also  seems  to  have 
certainly  been  precipitated  in  the  native  state  in  many  instances 
'Z.VZ'Z'i.     The  chemical  reactions  involved  in  the  introduc- 


(ndd  Field  and  tliose  of  California."  Awcr.   Jour.    Sci.,  ii.,  XXVT.,  V2H. 
h'eniarks  on  the  Extent  of  tlu'(i(ild  Ift'^^ion  of  California  and  Oicf^on," 
ctr  .  Jbhl.,  ii..  XX.,  T2.     "The   CarhoMiforous    A^e   of  a    I'orlion    of  the 
Gold  bearing  Roc'kH  of  California,"  Ihid.,  ii.,  XLV.,  2(i4.     W.  H.  Brewer. 
n')>ly   to  ahove,    //)/(/..  ii,  XI  A'.,  ;{!>T.   A.  Bowman,  "(ieolo<.cy  of  the  Sierra 
Nevada   in    rehition  to  V^ein  IMininj^,  '  .1////.  licsinircfs  W'c.sf  of  the   Uockji 
MoiiutaiiiH,  187.~»,  p.  441.     W.  H.  Brewer,  "  On  the  Age  of  the  (lold  hear- 
inj,'  Rocks  of  the  I'acilic  Coast,"  Aiiwr.  Jour.  Sci  .  ii.,  Xldl..  il4.      F.  (). 
Corning.  "The  Cold  Quartz  Mines  of  Crass  N'alley.  California,"  Kikj.  oiifl 
Milt.  Jour.,   December  11,  lH8(i,  p.  418.     W.  M.  Courtis,  "  (Jold  Quartz," 
Triiii.'i.  Aiiicr.  Inst.  Miii.   A'»f/.,  XVITT,  (!:«>.     H.  \V.  Fairbank.s,  "Ocolo^'y 
of  tiie  Mother  Lode,"  'I'ciitli  Ann.  Hep    Col.  Min.;  also  in   briefer  form  in 
Amcr.  Geol,  April,  IHKl,  p.  201.     Rec.     "On  the  Pre-Cretacoous  Rocks  of 
the  California  Coast  "RanKes,"  ^mcr.  CtCo/.,  Miirch,  lH<.)-,>:   February,   1H!);{. 
"The  Relation  between  Ore  Deposits  and  their  enclosin;:;  Walls,"  Kioj.  oiid 
Mill,  ./our.,  March  4,  l«!t:{,  ^>()().     .1.  H,  liamniond,  ".MiniiiKof  (iohl  Ores 
in  California."  7t'/(f/t  .!/(//.   Rep.  State  Min.,   p  S.")3.  .  Reo.     P.  Laur,  "Du 
(lisenient  et   de  TExploration   de  I'Or  en    Californie,"  .1«».   r/cs   Miiira, 
Vol.  Ill,,  1803,  p.  413.     W.  Lind^'reri,  "The  Cold  Deposit  at  Pine  llill,  Cal 
ifiirnia,"  .flm<?J'.  Jour.  Sci.,  August,  18!)4,  93.     "The  Auriferous  Veins  of 
Meadow    Lake,  California."  A/^(;^  September,  IS!);'.,  301.     "Characteristic! 
i'Vatures  of  California  (iold  Quartz  \'eins,"  liiitt.  (Jcol.  Soc.  of  Amcr.,  VI., 
2-21,  IH!)5.     Rec.     "  The  Cold-Silver  Veins  of  Ophir.  California,"  Ann.  Rep. 
Dii:  U.  S.  Geol.  Surreij,  34!),  IS!),").     Rec.     (i.  W.  Mayiiard,  "Remarks  on 
(iold  Specimens  from  California,"  Trans.  Auicr.  /y/.s7.  Min.  Enij.,  VI.,  451. 
.IS.  Newberry,  "On  the  (ienesis  and  Distribution  of  (iold,".S(7/oo/  of  Mines 
l^hiarterly.  III.,  p.  16.     E.  E,  Olcott.  "On  the  Shaw  Mine,  Eldorado  Co.," 
with  a  cross  se(!tion.  Trans.  Amcr.  Inst.  Min.  Eni/.,  XXIV.,  ss;j,  1K!)4.     A. 
l.'iMiiond,    "Mining  Stati.stics,"     A'o.  /,   Cal.    Geol.  Siirrcj/  (tabular  .state- 
ment of  quartz  mining  and   mills  between  the  Merced  and  Stanislaus 
IMvers).     J.A.Phillips,  •■Mining  and    Metallurgy  of  (!old    and   Silver," 
al.'^o  treatise     on    Ore    Deposits,    p.    3.")4.       Rec.      C.    j\l.    Rolker,     ■•The 
Late    Operatious    in    the    Mariposa    Estate,"  Trans.  Amer.    Inst.    Min. 
l'-ii<l-<  VI.,  14!).     B.  Silliman,  •'  Notice  of  a  Peculiar  Mode  of  OcH'urrenee  of 
(iuld  and  Silver  iu  the  Foothills  of  the  Sierra  Nevada,  Califoriua,"  Amcr. 
■four.  Sci.,  ii.,  XLV.,  93:  Cal.  Acad.  Sci.,  Vol.  IU.,  p.  ^im.     W.  H.  Storms, 
•The  Wall  Rocks  of  California  Gold  Mines,"  Enij.  and  Min.  .lour.,  Feb- 
ru;iry  3:5,  1S!I,~),  173.     H.  1\I.  Turner,    review   of  recent   pajjers   by   11.  W. 
Fiiirbanks  and  others  on  California  geology.  \n  Aincr.  Geol.,  Jmie,  1893. 
Rec.     J.  D  Whitney,  Cal.  Geol.  Survey,   Geology,  Vol.   I.,  p.   313.     J.  S. 
WilMon,  "  On  the  Gold  Regions  of  California,"  Quar.  Jour.  Geol.  Soc,  Vol 
X,,  p.  308,  1854. 


I«l: 


'Ii> 


;):2 


KHMi's  (hh-:  nhi'o^srm 


turn  aud  precipitation  of  gold  in  its  characteriHtic  veins  have 
been  the  Hubject  of  conHidoratiou  and  investigation  by  many 
observerH,  eHpeoitiUy  in  Anntralia.  The  ahnoHt  invariable  as^d- 
ciation  of  thn  gold  with  silica;  itH  verj'  frecpieut  entangleniciit 
in  iron  pyriteH,  and  the  possibility  of  its  cljeniical  condjinatioii 
with  iron  pyrites  through  the  medium  of  silver  or  l)isn)utli  or 
tellurium,  are  all  important  factors  to  be  considered.  The  exist- 
ence of  silicate  of  gold  was  early  shown  by  Bischoff,  who  did 
not  fail  to  appreciate  the  possil)ility  of  its  having  played  an 
important  part  in  the  filling  of  veins.' 

The  solubilitj'  of  gold  in  solutions  of  ferric  sulphate  is  well- 
established,  although  the  amount  taken  up  is  small.  If  such 
auriferous  solutions  were  to  be  exposed  to  a  reducing  action. 
auriferous  pyrites  would  be  a  natural  result.  Experiments  by 
Richard  Pearce'  have  indicated  that  when  pure  gold  is  fiist-d 
with  jn-rites  it  still  remains  as  glol)ules  through  the  residting 
matte,  but  if  allo^-ed  with  silver,  bismuth  or  tellurium,  it  ap- 
parently combines  with  the  pyrites,  ( r,  at  all  events,  becomes 
invisibly  disseminated  in  it.  The  demonstrated  presence  of 
bismuth  aud  tellurium  in  some  auriferous  pyrites  as  mined 
and  the  peculiar  metallurgical  behavior  of  such  ores  give  good 
reason,  as  ]\lr.  Pearce  has  pointed  out,  tor  suspecting  that  tlie 
bismuth  aud  tellurium  have  exerted  a  strong  influence  in  the 
original  precipitation  of  the  gold.  Again,  the  wide  distrilm- 
tion  of  haloid  salts  in  Nature  and  the  notable  solubility  of 
the  haloid  compounds  of  gold,  gives  this  group  of  elements  uo 
small  theoretical  importance.  Taken  in  connection  with  alka- 
line salts,  especially  carbonates  and  sulphides,  the  formei  f 
which  is  an  active  solvent  of  silica,  considerable  light  m  ly 
be  thrown  on  the  chemistry  of  vein-formation.  Thomas 
Egleston'*  has  recorded  interesting  experiments  upon  the  sohi- 
bilitj'  of  gold  in  ammoniacal  compounds,  and  as  these    aro 

'  Gustav  BisfhofT,  "Lelirbucli  tier  Clieiiiischen  undphysikulisclieii  (icdl 
ogie,"  EcUtiou  WnA,  II.,  '2(i.-,4-2(ir)T ;  Edition  1S()(!,  ifl.,  843-84(5.  Tlie 
passage  is  omitted  in  tlie  Englisli  tiauslutiou  publislied  by  tlw  '  'p'  li 
Society. 

'  Richard  Peanre,  " The  Association  of  CJoM      Hh   •<'  lie 

West,"  Traits.  Axier.  Inst.  Min.  Eny.,  XVlll.  -^^         -I 

738. 

'  T.  Egleston,  "Tlie  Formation  of  (Jold  Nuggei,-.  and  Placer  Deposits," 
Trans,   ximer.  Inst.  Min.  Eny.,  IX.,  G33,  esjiecially  039,  '  ^i. 


77//V    rAClF/C  S/JU'/-:. 


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Thomas 
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viiHsc'henGeol 
S4H-846.    The 


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u-er  Deposits,' 


thought  l)y  G.  F.  Becker  to  have  beeu  factors  in  the  prod  net  iin 
of  the  cinnabar  depoaita  of  California  (see  5i.  ir).(i:i),  th(> 
reactions  may  be  suggestive.  Of  the  haloid  elements,  iodine 
has  been  given  particular  prominence  by  sin'cral  obsorvc^rs, 
notably  T.  A.  Kickard.'  Whore  a  reducing  action  is  re(juirod, 
organic  matter  in  the  wall  rocks  is  the  most  available  precipi- 
tating agent.  William  Nicholas  bad  laid  stress  upon  its  im- 
portance.'^ Below  is  given  a  list  of  the  other  principal  papers 
bearing  on  this  subject,"  but  attention  may  also  be  directed  to 
the  general  literature  of  California  gold  (h>positH  on  a  previous 
l)age.  Considerable  difference  of  opinion  {jnu'ails  as  to 
vvliether  the  gold  has  come  from  a  fine  dissemination  in  the 
marine  sediments,  which  received  it  from  the  ocean,  during 
tlieir  deposition,  or  whether  from  igneous  rocks,  from  which  it 
lias  beeu  dissolved.  Gobi  has  certainly  been  demonstrated  to 
exist  in  appreciable  (piantitios  in  sea-water'  and  also  to  have 
been  produced  by  crystallization  directly  from  an  igneous 
magma.' 

As  bearing  upon  this  last-named  point  an  extraordinarily 
thorough  and  patient  investigation  lias  been  carried  through 
by  Mr.  John  R.  Don,  of  Otago,  New  Zealand,  the  object 
of  which  was  to  demonstrate  by  actual  chemical  analysis 
and  assay,  the  source  of  the  gold  in  certain  Australian 
reefs.  Vein  matter,  country  rocks,  sea-water,  in  fact,  all 
the  possible  and  available  sources  of  gold,  were  subjected 
to  quantitative  analysis.  The  results  were  so  largely 
negative,  that  the  author  feels  compelled   to  go  back  to  the 

'  T.  A.  Rickanl,  "  Oriffin  of  the  Goldboarinf^  Quartz  of  the  Bendigo 
Kccfs,"  Trunn.  Amer.  lust.  Min.  Eng.,  XXII.,  2H\),  1H<);5.  and  discussion, 
p  7;!S. 

'  William  Nicholas,  "The  Origin  of  Cold  in  Certain  Victorian  Reefs." 
E)i(i.  and  Min.  Jottr.,  December  15,  1SS:{. 

'A.  Liversidge,  "  On  the  Aniouut  of  Cold  and  Silver  in  Sea  Water," 
Pror.  Roy.  Soc.  Neif  Sonfh  Walen,  Oi^tober  2,  IS!*.").  See  also  Chemical 
Vi'i.-s.  Hcptenihor  and  October,  ISUG.  147,  KiO,  KUi;  Mueiister,  ./()»)•.  .Soc. 
chrm.  Indusin/,  April  :^(».  lS9v'.  XI.,  Hoi.  E.  Sonstadt.  "On  the  Presence 
oMJold  in  Sea  Water,"  Idem.  October  4,  1872.  p.  1.5!). 

'  W.  P.  Blake,  "Gold  in  Granite  and  Plutonic  Rocks."  Trans.  Amer. 
l)iHf.  Min.  Eng.,  September,  1896.  G.  P.  INlerrill,  "(iold  in  Granite," 
.l(/(i')'.  Jonr.  Sei.,  April.  189(),  'Md.  W.  Moericke,  "Notes  on  Chilean  Ore 
I'il)usits,"  Tschermak's  Mineralogische  und  Petrogvaphische  Mitth.,  XII., 
mr,. 


Silii 


374 


KEMP'S  ORE  DEPOSITS. 


i 


deep-seated  sources  and  to  refer  the  gold  to  a  home  in  some 
rock,  Dot  available  for  assay.  Too  much  commeudation  can 
scarcely  be  given  to  the  thoroughness  aud  care  with  which  the 
investigation  was  carried  out.  The  quantitative  data  have 
placed  mining  geologists  the  world  over  under  a  great  debt.' 

2.12.20.  The  stratigra})hy  of  the  auriferous  strata  in  the 
Sierras  was  briefly  referred  to  above  as  involving  Paleozoic 
and  Mesozoic  strata.  It  would  be  impossible  and  undesirable 
to  give  in  this  place  any  complete  bibliography  of  the  subject, 
but  in  the  papers  of  Diller,"  J.  P.  Sniith^  and  Turner/  cited 
below,  quite  full  references  are  to  be  found  to  earlier  work.  In 
the  atlas  sheets  of  the  U.  S.  Geol.  Survey  local  names  are  given 
to  the  various  formations,  which  are  classified  on  the  physical 
basis  as  outlined  in  the  introduction  (]. 01.01),  but  as  regards 
geological  time,  strata  have  been  identified  as  follows:  Pre- 
Silurian  crystalline  schists;  Silurian  quartzite  and  slate, 
v;ith  included  lenses  of  limestone;  Devonian  corallii-.e 
limestone;  pi-obably  both  Lower  and  Upper  Carbonif- 
erous argillite,  quartzite,  mica -schist,  and  metamor- 
phosed tuffs;  various  Triassic  and  Jura-Trias  sediments 
more  or  less  metamorphosed ;  Jurassic  slates ;  Cretaceous 
(Chico)  sandstone;  Tertiarj- and  Quaternary  sandstone.  san(1.«, 
gravels  and  clays.  (See  pp.  2"i.S-:i41i  of  first  paper  of  H.  \V. 
Turner,  cited  below.     Also  Diller  op.  cit. ) 

In  the  auriferous  belt,  J.  P.  Smith  has  admitted  the  presence 
of  Silurian,  Carboniferous,  Triassic  and  Jurassic  strata,  but 
rejects  Cretaceous. 

:i.  12.24  Our  knowledge  has  aloO  increased  of  late  regarding 
the  intrusions  of  granite  and  the  relations  of  the  various  sedi- 
mentary formations  to  the  old  basei^ient  upon  which  they  were 
laid  down.     The  work  of  H.  W.  Fairbanks,  often  cited  in  the 


'John  R.Don,  "The  Genesis  of  ceitain  Auriferous  Lodes,"  Trans. 
Amcr.  Inst.  Min.    Eikj.,  XXVTT..  :)(i4.  1H<)7. 

-  .F.  S.  Diller  and  Cliarles  Schui-liert.  "  Disc^overy  of  Devonian  Rooks  in 
Californiii,"  Aiiirr  Joitr.  Sci.,  June.  1S!)4,  41tl. 

'J.  P.  Smith,  "  A^e  of  the  Auriferon.s  Slates  of  the  Sierra  Nevada," 
Bnll.  Geol.  Soc.  Amcr.,  V.,  24:},  1S94. 

'  IT.  W.  Turner.  "  fleolofxical  Notes  on  the  Sierra  Nevada,"  Aiiier.  G"ol., 
April  and  May,  IH!14.  22H-*.".t7.  Further  contributions  to  the  "Geology  of 
the  Sierra  Nevada,"  A'T7^.  Ann.  Rep.  Dir.  U.  S.  Geol.  Survey,  521-740. 
"  Granitic  Rocks  of  the  Sierra  Nevada,  '  ,/our.  of  Geo!.,  March,  1899,  141. 


THE  PACIFIC  HLOPE. 


375 


m 

ill 


iruer/  cited 


r;i  Nevada," 


text,  and  that  of  the  U.  8.  geologists,  Becker,  Diller,  Turner 
Hiifl  Lindgreu,  have  been  bringing  out  forcibly  the  intrusive 
imtare  and  Mesozoic  age  of  much  of  the  granite  of  the  Sierras 
and  of  the  Coast  range.  Most  recently  among  the  Canadians 
(i.  M.  Dawson  has  traced  similar  effects  to  the  north,  and  A. 
C.  Lawaon,'  from  an  extended  survey  of  the  western  coast,  and 
search  in  the  literature  of  Mexico,  Central  and  even  South 
America,  forcibly  portrays  the  advance  of  tbe  great  granitic 
"liatholites"  {i.<\,  plutonic  masses)  toward  the  surface,  the 
fusing  into  their  magmas  of  the  overlying  strata,  and  the 
metamorphic  effects.  All  these  cannot  but  be  strong  factors  to 
be  considered  in  connection  with  the  ore  bodies,  and  as  time 
goes  on  this  counectiou  will  probably  be  shown. 

In  regard  to  the  otber  forms  of  igneous  rocks  involved  in  the 
j^^old  belt  and  often  greatlj'  metamorphosed,  we  aif  advancing 
rapidly  in  knowledge.  These  were  referred  to  earlier  under 
■.M'J.IO,  but  in  his  review  of  the  igneous  rocks  Mr.  Turner 
cites  nearly  the  entire  series  of  plutonic  and  eff'usive  types.  In 
many  instances  the  more  basic  members  have  passed  under  the 
influence  of  dynanio-metamorphism,  into  amphibolites  and 
talcose  rocks,  but  in  other  cases  the  dikes  and  slieets  are  still 
little  if  at  all  changed.  Great  areas  are  formed  of  them  or 
involve  them,  and  lead  to  the  inference  that  they  have  not  been 
without  their  influence  "n  promoting  ore  bearing  circulations. 

Ml'.  Turner's  recent  review  of  the  geology  of  the  Sierras''  is 
important,  not  alone  in  its  bearings  on  local  geology,  but  upon 
theoretical  petrology  as  well.  The  folios  of  the  U.  S.  Geologi- 
cal Survey  now  embrace  a  large  portion  of  the  gold  belt,  and 
are  much  the  most  available  expositions  of  the  geological 
structure.  They  are  listed,  so  far  as  yet  issued,  in  the  footnote 
to  paragraph  2.12.00. 

'  A.  C.  Lawson,   "The  C'ordilleran  Mesozoic  Revolution,"  Journal  of 
ecology,  I.,  r)Tit,  18i);5. 
''  Aitwr.  Gcol,  May,  1804,  pp.  3nr-:un. 
••  XVII.  Ann.  Rep.  Div.  U.  S.  Geol.  Survey. 


CHAPTER  XIII. 


GOLD   ELSEWHERE   IN    THE   UNITED   STATES   AND   IN    CANADA. 

^.i;}.01.  Example  45a.  Southern  Appalacbiaus.  Gold- 
quartz  veins  and  veiulets  and  auriferous  impregnations  of  the 
country  rocks,  which  are  almost  iuvariahl}'  of  metamorpliic 
types,  and  which  are  of  considerable  varietj'.  From  these, 
placers  have  resulted,  both  by  superficial  decay  and  byerosiou. 
The  general  gei  logy  of  the  southern  Atlantic  States  bus  been 
outlined  in  the  introduction.  Reference  maj' again  be  made  to 
the  Coastal  Plain  of  Quaternary.  Tertiary,  and  Mesozoic  sedi- 
mentary strata,  and  to  the  crystalline  and  metamorphosed  belt, 
lying  west  of  it.  In  the  latter  are  found  the  gold  deposits. 
Increasing  observation  tends  to  show  that  the  (juartz 
veins  are  all  fillings  of  fissures,  which  have  been  pio- 
duced  in  the  geological  disturbances  to  which  the  region 
has  been  subjected.  The  smaller  reticulations  indicate 
crushings,  more  or  less  intimately  related  to  the  gen- 
eral production  of  sciiistosity,  but  the  larger  veins  often  cut  the 
schistosity  at  a  notable  angle  and  clearly  have  been  produced 
by  fairly  extended  dislocations.  All  are  deposited  in  what 
Posepny  has  called  "spaces  of  discission."  The  wall  rocks 
embrace  both  metamorphosed  sediments  and  metamorphosed 
igneous  rocks.  The  latter  are  both  of  volcanic  and  {)lutouic 
origin,  and  the  altered  volcanics  may  closely  resemble  slates. 
Foliation  is  everywhere  developed.  Dikes  of  diabase,  little,  if 
at  all,  metamorphosed,  are  present  in  some  districts  of  North 
Carolina,  and  have  certainly  exercised  a  favorable  influence  on 
the  ore  deposition.  In  all  parts  of  the  gold  territory  the  super- 
ficial decay  has  been  pronounced,  and  the  rocks  are  extensively 
decomposed  to  depths  that  may  reach  over  100  feet.  Siub 
material  has  been  called  by  Becker,  saprolite,  meaning  by  the 


GOLD  IN  UNITEI)  STATES  AND  CANADA. 


377 


word  a  geueral  term  for  decomposed  rock,  whatever  has  been 
its  original  character.  Laterite  has  been  earlier  used  in  the 
same  sense  and  has  priority.  The  ores  are  oxidized  in  these 
decomposed  walls  and  the  whole  mass  may  be  hydraulicked, 
the  free  gold  being  caught,  and  the  boulders  of  gold  (juartz 
being  concentrated  for  milling.  The  laterite  also  works  down 
hill  from  its  original  position,  and  has  been  called  in  this  con- 
nection "frost-drift"  by  Kerr.  Natural  erosion  has  led  to  the 
formation  of  the  usual  type  of  placers,  and  these  have  been 
worked  more  or  less  in  earlier  years,  and  aro  still  productive  in 
a  small  way.  Above  the  level  of  the  ground-water  the  veins 
chiefly  afford  free  milling  ores,  but  below  it,  they  pass  into 
more  rebellious  sulphurets  of  the  usual  types.  The  mineralogy 
of  the  veins  is  similar  to  that  of  the  usual  run  of  gold-quartz 
veins,  but  in  the  aggregate  presents  considerable  variety. 
Becker  records  a  total  of  oil  minerals,  of  which  45  are  original, 
and  14  secondary.  The  gold  is  at  times  found  in  the  country 
r<»ek  along  (]uartz  veins,  aiid  sometimes  in  rock  free  from  vein 
formations,  but  it  is  presumably  of  secondary  introduction. 
The  garnets  of  a  mica-schist  near  Dahlonega,  Ga.,  have 
been  proved  by  Becker  to  be  notably  auriferous.* 

'  The  following  palmers  refer  to  the  gold  deposits  of  the  Southern  Appa- 
lacluans  in  general;  suhseiiueiitly  jKipers  are  groujied  by  States.  G.  F. 
Hffker's  pajter,  cited  below,  contains  a  quite  comjilete  l)ilih<)grai)hy,  ])p. 
T<)-T;{,  clironologically  arranged,  ilown  to  1S!)4.  Acknowledgments  are 
lii'itMuadetoit.butadditioual  i)apersare  also  given.  W.  H.  Adains,  "(lold 
Milling  in  the  Ai)i)ala(!hian  Belt."  Etuj.  diid  Miii.  Jour.,  July  4,  ISlMJ,  j).  7. 
\V.  R.  HaU^h,  "Klines,  .Miners  and  Mining  Interests  of  the  United  States," 
1SS2,  p.  1102.  G.  F.  Becker,  "  Reconnai.sssmce  of  the  Gold  Fields  of  the 
Simtheru  A|)iKilaciiians,"  A'TV.  .1/*//.  Rip.  Dir.  U.  S.  Gcnl.  Snrrcif,  i'art 
II.,  l.S!)").  Rec.  F.  C.  Hand,  "Southern  ({old  Fields,"  Eiiy.  aiid  Miii. 
Jour..  December  T,  18S9,  p.  4!>r).  W.  C.  Kerr,  "  On  the  Action  of  Fro.st  in 
till'  Rearrangement  of  Sujierticial  Karthy  Material,  '  Auwr.  Jour.  Sci., 
XXL,  ISSl,  :{4.-).  O.  :\l.  Lieh(>r,  'A  Contrilmtion  to  the  Geologic  Chronol- 
ogy of  the  Southern  ApiKiiachians,"  Prop.  Aiiirr.  A.s.'ioc.  Adr.  Sci.,  XII., 
l^V.),  227.  P.  II.  Mell,  ••  Auriferous  Slate  Deposits  of  tlie  Southern  Ap|)a- 
lachians,"  Troti.s.  Ainer.  ///.s7.  Miii.  Enij..  IX.,  ;5!»it;  Emj.  (Did  Min.  Jour., 
.IiMiH  11,  ISsl,  :j<)7.  H.  B.  0.  Nitze,  "  Present  C'.ndition  of  Gold  Mining  in 
the  Southern  Appahichian  States,"  Idem,  X>V.,  <i(il.  Discu.ssion,  1021, 
1112.").  Rec.  A  review  by  Robert  Peeic  in  the  :'''hoi>I  of  Minis  (,)iiiirf(rli/, 
•lainiary,  189(J,  177,  is  a  vahiable  di.scussion.  See  also  forthcoming 
Hidlctin  17,  N.  C.Gi'ol.  Survey.  E.  G.  Spilshury,  "Notes  on  the  General 
Treatment  of  the  Southern  (iold  Ores  ami   Experiments  in  Matting  Iron 


378 


KEMP'S  ORE  DEPOSITS. 


2.13.02.  Becker  has  broadly  divided  the  auriferous  area  into 
three  great  l)elts :  the  Georgian  belt,  extending  from  Montgom- 
ery, Ala.,  through  Dahlonega,  Ga,,  to  the  Boilston  IVliue  in 
North  Carolina ;  the  South  Mountain  belt,  embracing  a  group  of 
mountains  of  this  name  in  North  Carolina;  and  the  Carolinian 
belt,  lying  far  to  the  east  of  the  latter  and  ranging  from  South 
Carolina  two-thirds  across  North  Carolina.  The  Virginia  de- 
posits lie  in  the  same  line  further  north.  So  far  as  North  Caro- 
lina is  concerned  this  classification,  as  shown  later,  has  been 
amplified  by  Nitze. 

2.1:5.0.3.  Alabama.  The  gold-bearing  belt  begins  in  Ala- 
bama on  the  southwest  and  covers  in  this  State  a  triangular 
area  some  IM)  miles  on  a  side  and  situated  about  the  middle  of 
the  eastern  boundary.  In  all  nine  counties  are  embraced.  The 
country  rock  consists  of  the  Talladega  series  of  slates,  quartz- 
ites,  conglomerates,  and  dolomites;  and  of  a  complex  series  of 
gneisses,  diorites,  green  schists,  granites  and  some  basic  dikes, 
besides  other  minor  varieties  of  rocks  of  igneous  affinities. 
The  Talladega  series  contains  a  large  proportion  of  the  gold 
mines,  but  otliers  are  known  in  the  gneisses,  diorites  and  green 
schists.      The  veins  are  commonly  parallel  to  the  foliation.' 


Sulpliitlos,"  rnnis.  Aiiwr.  Inst,  ^fi)l.  Em/..  XV.,  TfiT.  J.  W.  Taylor,  "The 
(Jolil  iiud  Silver  -Mini's  East  of  tlie  Rocky  ]\rouiitaiiis,"  ximer.  Jour  of  Min- 
ing, II.,  IJSK),  ISGT.  J.  D.  Whituey,  Metallic  Wealth  of  the  United  States. 
18,")4.  Volume  XTII.  of  the  Tenth  Censii.s,  on  the  PreiMcms  ^lotals.  has 
valuable  statistics,  ami  the  voluiue  on  the  Mineral  Industries  of  the 
Elexvnth  Cenaus  has  hiter  ones. 

'  The  following  references  may  be  consulted  on  Alabama.  Attention  is 
also  called  to  the  general  references  in  the  preceding  footnote,  that  refer 
to  the  Southern  Apimlachiaus.  Anonymous,  "Notes  on  the  .Alabama  (iolil 
Belt,"  Eii(i.  and  Min.  Jour.,  January  2(»,  1S94,  ]>.  57.  W.  M.  Brewer. 
"The  Arbacoochee  Hold  District,  Ala.,"  Idem,  August  17,  ISO"),  \\>i. 
W.  M.  {{rewcr,  "The  (iold  Regions  of  (ieorgia  and  Alabama."  Trans. 
Ainer.  Inst.  Min.  Eng..  XXV.,  56!).  "The  Upper  (Iold  Belt  of  Alabama." 
Bnlletin  .7.  Ahdxnna  Geol.  Snrrei/,  ISflO.  contains  su])]>lenientary  notes  by 
E.  A.  Smith,  and  valuable  i)etrographical  descriptions  by  J.  M.  Clemeiits 
and  A.  H.  Brooks  :  a  few  also  by  C.  W.  Hawes.  Rec.  J.  L.  Camj)h('il 
and  W.  IT.  RufTner.  ".\  Physical  Survey  from  .Atlanta,  Ga.,  across  Ala 
bama  and  ]\Iississip]>i  jheAIississippi  River,  along  the  line  of  the  (leorgia 
racific  R.  R.,"  New  ^  ork.  IHH:?.  87.  O.  M.  Lieber  refers  at  length  to 
Alabama  placers  in  his  pai)er  on  "  Der  Itacolumit,  seine  Begleiter  imd  die 
^letallfiibrung  desselben:  (lanf/stndi^'n."  111.,  especially  pj).  HMi  and  t"! 
lowing.     \V.  B.  Phillips,    •  The  Lower  (Iold  Belt  of  Alabama,  '  IhiUeti.i  ., 


GOLD  IN   UNITED  STATES  AND  CANADA. 


379 


Geographically  the  gold  region  is  sometimes  divided  into  the 
Lower  Belt,  comprising  Coosa,  Tallapoc^a,  Chambers  and  part 
of  Chilton  counties,  and  the  Upper,  in  Cleburne,  Clay,  Kan- 
(lolph  and  part  of  Tallad«?ga  counties. 

:*.  13.04.  Georgia.  The  metamorphic  areas  containing  the 
H'old  of  Alaban.a  are  continued  across  Georgia  in  a  northeasterly 
Jine,  with  a  general  strike  of  the  foliation  between  30  and  50 
(legrees  N.  E.  The  dip  is  southeast.  Gneiss  and  schists  pre- 
vail, but  igneous  rocks  are  not  unknown,  Dahlonega  is  the 
chief  mining  center,  and  has  important  hydraulic  works  and 
stamp  mills  in  operation.^     The  decomposed  rock  is  hydrau- 


Alabmna  Geol.  Swvey,  1803.  Rec.  J.  W.  Spencer.  "  Economic  Geologi- 
cal Survey  in  Georgia  and  Alabama,  along  the  Macon  and  Birmingliam 
Railroad,  1S89  "  (cited  by  ({.  F.  Becker).  M.  Tuomey,  "  First  Biennial 
Report  on  the  Geology  of  Alabama,"  iy4T-18-li),  is.jO.  Second  ditto,  1855, 
1S58. 

'  Attention  is  called  to  the  general  i)ai)ers.  earlier  cited.  Adelberg  and 
Raymond,  "Report  on  the  Lewis  Gold  Mine,"  1S()6.  "  ReiK)rt  on  the 
ON'eil  Proiierty,'  186().  W.  P.  Blake,  "ReiKnt  on  the  Gold  Placers  of 
Lumpkin  County,  Ga.,"  etc.  (small  book  published  by  J.  F.  Trow,  New 
York, 1858).  See,  also,  Anwr.  Jour.  <SV«.,  ii..  XXVI. ,  2T8;  Mitdng  uiulSfafis- 
tiidl  Magazine,  X.,  Aiil,  47(5,  18.58.  "On  Placer  Gold  Mines  in  (Georgia,  ' 
t'tc,  Pi'oc.  Aimr.  A.'isoc.  Adv.  Svi.,  1859.  "Notes  and  Recollections 
Concerning  the  Mineral  Resources  of  Northern  (Jeorgia  and  Western  North 
Carolina.  '  Triiii.^.  Aiiw):  lust.  Mill.  Einj.,  XXV.  79(t,  1S95.  \V.  II.  Brewer. 
"The  Dahlonega  Gold  Mining  District. "  £«(/.  and Min.  Jour.,  December  15, 
1SSI4,  .559.  "  New  Work  in  the  Villa  Rica  District,"  Lhin.  June  30,  1897.  II . 
Credner,  "  Besdu'eibung  einer  paragenetisch,  intere.ssanter  Goldvorkom- 
nu>n  in  Georgia,  Nord  Amerika."  iW^tcs  ./a/(?'6i<o/t,  1867,  443.  "  Geognos- 
tisdie  Skizze  der  (ioldfelder  von  Dahlonega,  (Georgia,  Nord  America," 
Z,'il.<rhr.  (Id.  Geol.  (JcscUs.,  XIX.,  ^4,  18()7.  C.  T.Jackson,  "Minerals 
Horn  (Jeorgia,"  Proc.  Bosf.  Soc.  Nat.  Hist.,  VII.,  23,  1801.  J.  B.  Mackin- 
Kish,  "The  (rold  Mining  District  of  Daldonega,  Ga.."  Eiig.  aiitlMin.  Jour., 
XXVII.,  3.58,  1879.  P.  H.  Mell,  "Papers  on  Gold  Mining  in  Georgia." 
/'.'(/</.  and  Miti.  Jour.,  October  (5  and  1:5,  1877,  pp.  3:i8,  375  ;  also,  p.  .538; 
August  10  and  17,  1878.  i)p.  97.  IKi.  P.  C.  Morton.  "Mineral  Resources  of 
(ifdrgiu,"  Aincr.  Jour.  Mining.  I.,  3(i5,  ISfifi.  J.  Peck,  "Tlie  Mining  Region 
"f  Georgia,  Western  North  ( 'art)lina  and  East  Tennessee,  '  Amcr.  Jour. 
Sri.,  i.,  XXIII.,  4,  1833.  Wm.  Phinii)s,  "Es.say  on  the  Georgia  Gold 
Mines," /(?(')«.  i.,  XXIV..  1.  G.  U.  She])ard.  "  On  Lazulite,  Pyroithyllite, 
and  Tetradymite  in  (Georgia."  Idem,  ii.,  XXVII.,  '.W,  1859.  J.  W.  Spencer, 
see  under  .Mabama.  H.  G.  Torrey,  "Tests  of  Dahlonega  Gold  Ores,"  Eng. 
'iii((  Mill.  Jour.,  January  5,  1895.  3  "Yeate.s,  McCallie  and  King;  Gold 
I  If  posits  of  Georgia."  Geol.  Surrey  of  Georgia,  Bulletin  4.  1896. 


380 


KEMP'S  ORE  DEPOSITS. 


linked,  the  quartz  boulders  are  caught  and  are  then  run  through 
stamps. 

a.  13.05.  South  Carolina.  The  mines  in  this  State  are  on  the 
southern  extension  of  the  Carolinian  belt  in  Lancaster,  Ches- 
terfield and  Union  counties.  The  Haile  is  one  of  the  beyt 
known,  and  affords  an  ore  consisting  of  impregnated  miiscovite 
schist,  that  is  an  altered  pre-Cambrian  volcanic,  according  to 
Becker.  The  rich  portions  occur  along  intruded  diabase  dikes. 
The  Brewer  mine,  a  few  miles  away,  has  similar  wall  rock.' 

2.  lo.Of).     North  Carolina.     TheGeorgianbeltof  Becker  just 
reaches  North  Carolina,  the  South  Mountain  belt  lies  wholly 
within  it,  and  the  Carolinian  belt  passes  through  its  eastern  or 
eastern  central  portion.      Nitze  and   Hanna  divide  the  gold- 
bearing  areas  of  the  State  into  six  belts,  which  are  from  east  to 
west.   (1)  The  eastern  Carolina  belt,  in  Warren,  Halifax,  Frauk- 
lin  and  Nash  counties.     Quartz  vein  lets  are  found  in  diorite, 
chlorite  schist  and  gneiss.      (2)     The  Carolina  slate  belt,  ex- 
tending southwest  across  the  State  from  Person  to  Union  comi- 
ties.    The  mines  are  mostly  in  Randolph,  Davidson,  Montgom- 
ery, Stanley  and  Union  counties.     The  wall  rocks  are  slates 
and    volcanics.      Diabase  dikes  exert  a   favorable   iuHuence. 
(o)     The     Carolina    igneous    belt,    chiefly   in    Mecklenburg. 
Cabarrus,  Rowan,  Davidson  and  Guilford  counties.     The  rocks 
are  granite,  diorite,  gabbro  and  diabase,  and  are  later  than  the 
slates.     The  gold -quartz  veins  often  carry  copper.     (4)     The 
King's  Mountain  belt,  in  Gaston,  Lincoln,  Catawba,  Davie  and 
Yadkin  counties.     The  rocks  are  crystalline  schists,  gneisses, 
siliceous  limestones  and  quartzites.     The  ores  are  sometimes 
impregnated   streaks  of  country    rock,  and   again   are  quartz 
veins.     The  King's  Mountain  mine  has  ores  in  siliceous  lime- 


'  Attention  is  oilled  to  tlie  pjenoral  papers  earlier  cited.  G.  E.  Ladsliaw. 
"  Si)artanl)ur^,  Soutli  Carolina.  Gold  Fields," -fi'**//.  and  Min.  Join:.  Auly 
16,  1892,  52.  O,  M.  Lieber,  "Reports  of  the  Geological  Survey  of  South 
Carolina."  18r)G,  1S,-)S,  IS.-)}),  18(i0.  "  Gold  in  South  Carolina  "is  often  n- 
ferred  to  in  Lieber's  ixiper  on  "  Itacolnniit,"  etc.,  Oaiirjstndii'ii,  111.,  vinlt, 
405,  ff.  R.  Mills,  "  (xold  Occurrence.s  in  South  CaroWun."  in  Stati.'itic'i  of 
South  Carolina,  1820.  pp.  26,  071.  E.  G.  Spilsbury,  "Gold  Jlining  in 
South  Carolina,"  Trann.  Amer.  Lhtt.  Min.  Eng.,  XII.,  09,  1884.  A.  Tliies 
and  E.  Metzger,  "Geology  of  the  Haile  Mine."  Idem,  XIX.,  595,  1890.  A. 
Thiesand  W.  B.  Phillips,  "The  Thies  Process,  etc.,  at  the  Haile  Muic 
Idem,  XIX.,  601,  1890. 


UOLU  IN   UNITED  STATES  AND   CANADA. 


381 


stone,  and  is  a  well-known  one.  (5)  South  Mountain  belt,  in 
Burke,  McDowell  and  Rutherford  counties.  The  rocks  are 
mica  and  bornblende  gneisses  and  scbists,  with  pegmatites  and 
some  minor  pyroxenic  varieties.  Quartz  veins  in  true  fissures 
are  the  rule.  They  can  be  classed  into  five  sub-belts,  (d) 
Gold  deposits  west  of  the  Blue  Ridge  in  Ashe,  Jackson,  Tran- 
sylvania, Macon  and  Cherokee  counties.  The  rocks  are  gneis- 
ses and  schists  vvth  quartz  veins.  The  Bulletin  by  Nitze  and 
Hanna,  cited  below,  givesdetailsfromall  the  mines  of  the  State.' 
2.13.07.     Virginia,  Maryland  and  the   Northern  States. 


'  Attention  is  called  to  the  general  ('itations  earlier  {^iven.  W.  P.  Blake, 
'Ueniarks  on  the  Minerals  and  Ancient  Mines  of  tlie  Cherokee  River 
V'alley,  N.  C,"  Proc.  Aviei:  Assoc.  Adv.  Sci.,  185i).  L.  S.  Burbank,  "  Sur- 
lace  Geology  of  North  Carolina,"  Proc.  Bosf.  Soc.  Nat.  IJist..  tsTU,  1.")!. 
11.  M.  Chance,  "Auriferous  (travels  of  North  Carolina,"  ^Ihu'/-.  Phil.  Soc, 
1881,  477.  H.  E.  Colton,  "Mining  in  North  Carolina,"  Eng.  and.  Min. 
.lour.,  IHTl.  ii'2;5.  H.  Credner,  "  Keport  of  Kxi)lorations  in  tlie  (lold  Fields 
:i!'  Virginia  and  Nortli  Carolina,"  Amer.  Ju'ui:  of  Miiiiiii/,  18(18,  ;5(U,  ^77.  ',VJ',), 
|i)7.  W.  B.  Devereux,  "(told  and  It-s  Associated  ;\liuerals  at  King's 
Mountain,  N.  C,"  Eikj.  and  J///(.  Jour.,  January  la,  1881,  3Sl.  M.  \V. 
Dickeson,  "  Report  on  the  Brown  and  Kdwards  Properties,"  1800.  "  Report 
oil  the  Rhea  Mine,"  18()().  A.  Eaton,  "The  (Jold  of  the  Carolinas  in  Tal- 
cose  Slate,"  ^mer.  Jour.  Sci.,  i.,  XVIII.,  .W,  ISaO.  E.  Emmons,  "Geolog- 
ical Report  upon  the  Midland  (^ounties  of  North  Carolina,"  18!)().  F.  A. 
(Ifiith,  "Contributions  to  American  Mineralogy,"  ^Iw/c/'.  Jour.  Sci,  ii., 
XIX.,  18,  1855  ;  ii.,  XXVIII.,  24(5,  18,^)!).  "Report  on  the  Stewart  Mine," 
l^^ofi.  f^ee  Jonnxd of  tlie,  Fraxhiiii  liisfitiitc,  November,  December,  18TI, 
"  Mineral  Resources  of  North  Carolina,  '  in  Kerr's  JRtjtorf.  1875,  Appendix 
C.  "The  Minerals  and  Mineral  Localities  of  North  ('arolina."  ]iriiited  for 
tiie  State  Board  of  Agriculture,  Raleigh,  1885.  "  The  Minerals  of  North 
Carolina,"  Bulletin  74,  U.  S.  Geol.  Survey,  18!)1.  J.  U.  Cibbon,  "Letter 
on  the  Gold  of  North  Carolina."  Amer.  Jour.  Sci.,  i.,  XLVIIL,  898,  18-44. 
v.  v..  Hand,  "Southern  Gold  P'ield.s,"  Eng.  and  Min.  Jour.,  December  7, 
l^'Sit,  49,5.  G.  B.  Hanna,  "The  Fineness  of  Native  Gold  in  the  Carolinas 
and  (ieorgia,"  Idem,  Sei)teniber  18,  188(5,  201.  See,  also,  under  Kerr  and 
under  Nitze.  O.  J.  Heinrich,  "On  Gold  Hill,  N.  C,"  Tran.<i.  Avie7'.  Ivst. 
Min.  Eng.,  IL,  824,  1874.  J.  A.  Holmes.  "  Forthcoming  Tinlletin  17,  North 
Ciirolina  (Geological  Survey,  with  a  Ceologica!  Bibliography,"  in  jrt-epara- 
tion,  1897.  C.  L.  Hunter,  "Notice  of  the  Rarer  Minerals  and  of  New  Lo- 
calities in  Western  North  Candina,"  Amer.  Jour.  Sci.,  ii.,  XV.,  875,  1858. 
C.  T.  Jackson,  "Reix)rt  on  the  McCuUock  Cop|)er  and  Gold  Mining  Co.." 
1853.  W.  C.  Kerr,  "Geological  Report  on  North  (  .irolina,"  18(i!)  ;  ditto, 
'i^'iiy.  "  Gold  Gravels  of  Nortli  Carolina,"  Trans.  Av::r.  Inst.  Min.  Eny., 
Vin.,  462.  "  Some  Peculiarities  ii\  the  Occurrence  of  (iold  in  North  Caro- 
lina," Idem,  X.,  475,  1882.     "On  the  Action  of  Frost  in  the  Arrangement 


382 


KKMP'H  OHM  DEPOSITS. 


The  Carolinian  belt  of  Becker  extends  into  Virginia,  an  '  has 
been  the  basis  of  some  mining.  The  usual  type  of  (juartz  veinlets 
in  schists  is  met.  The  belt  runs  through  the  State  east  of  tlie 
Blue  Ridge.'     Several  small  mines  have  been  developed   in 

of  SuiHJi'ticial  Eartliy  Material,"  Anmr.  Jour.  Sci.,  iii.,  XXI.,  345,  lb81. 
S.  P.  Leeds,  "Reports  on  tlie  Karrioker,  tlie  Rliyiner,  and  the  l?iidisill 
Mines,"  1H,*)4.  O.  M.  Lieber,  "Ueber  das  (iold  vorkonnnen  iu  Nord  Caro- 
lina," Gamjtiiudien,  HI.,  2r,M,  IHliO  ;  also,  417.  Jules  Marcou,  "On  Gold 
in  North  Carolina,  '  P/w.  Bout.  Soc.  Nat.  Hist.,  JX.,  AT,  ^Hi\2.  A.  IMetz- 
ger,  "  Tile  Gold  Mines  of  Nortii  Carolina,"  Kikj.  (ititlMin.  Joki:,  Octol)er, 
24,  1891,  480.  E.  Jlitchell,  "On  the  (ieology  of  the  Ciold  Region  of  Nortli 
Carolina,"  Amvr.  Jour.  SvL,  i.,  XVI.,  !i>,  18;^!).  II.  H.  C.  Nitze,  "The 
Genesis  of  tlie  (iold  Ores  in  the  Central  Shite  Melt  of  the  Carolinas,"  Eikj. 
(t)i(i  Mill..  Jour.,  June  I!).  iSiC.  II.  H.  C.  Nitze  and  (i.  H.  JIanna.  'Gold 
Depo.sits  of  North  Carolina,"  Bulletin.!,  N.  C.  Ueol.  Survey,  \mil.  Rec. 
II.  13.  C.  Nitze  and  A.  J.  Wilkins,  "Gold  ^lining  in  North  Carolina  iiiid 
other  Appalaehian  State.s,"  linllclin  X..  Idem  (in  preparation),  181(7,-  see. 
also.  Trans.  Aiiier.  hint.  ]\liii.  Kiiij.,  XXV.,  (i(51.  D.  Olmstead,  "Gold 
Mines  of  North  Carolina,"  Aiiier.  Jour.  Sei.,  i.,  IX.,  Ti,  18','."">.  C.  E.  Rotlie, 
"Remarks  on  the  Gold  Mines  of  North  Carolina,"  Idem,  i.,  XIII.,  iidl. 
1828.  C.  U.  Sliei«ird.  "Report  on  the  (lold  Hill  Mine,"  ISn:}.  "Gold  in 
North  Carolina,"  N.  Y.  Miiiiiiij  Magazine,  X.,  371,  18.>S  ;  XI.,  13(5.  V.  L 
Smith,  "  Notice  of  Some  Faots  Conneete<l  Avith  the  (Jold  of  a  Portion  uf 
North  Carolina,"  .Imc/-.  Jour.  .SV/.,  i.,  XXXIl.,  130.1837.  R.  P.  St<'veiis. 
"Gold  in  North  Carolina,"  Ainer.  Joiir.  Mi.i.,  I.,  313,  IHCC.  R.  C.  Taylnr, 
"Rep<»rt  on  the  Washington  Silver  Mine,"  1845.  P.  T.  Tyson.  "Rcik^ii 
on  the  (iold  Dejiosits  of  the  iMateo  .Mining  Co.,"  18.10.  Arthur  \Vin^lo^\, 
"Gold  ]Mines  in  North  Carolina,"  Eikj.  anil  Miii.  Jonr.,  XL.,  2\H,  188.'i. 

'  .Vttention  is  called  to  the  general  referencies  on  the  Sonthern  Stat«'>, 
earlier  given.  J.  L.  Campbell,  "(ieology  and  Mineral  Resources  of  tlu' 
James  River  Valley,"  p.  90,  New  York,  G.  P.  Putnam's  Sous,  1882.  A  I. 
stract  in  Kii(f.  and  Min.  Jour.,  Sei>temher  9.  1882,  13r».  T.  <i. 
Clemson,  "  The  Gold  Region  of  Virginia,"  Traii.s.  Ueol.  Soe.  Penii..  '.M',^. 
183.').  H.  Credner,  "Re|)ort()f  Explorations  in  the  (iold  Fields  of  Virginia 
and  North  Carolina,"  Ainer.  Jour,  of  Miniiii/,  18(i8,  pp.  3')1,  377,  393,  Wi. 
"(Jeognostische  Skizzen  aus  Virginia,  Nord  Amerika,"  Zeitxehr.  d.d. 
Geol.  (r'('.s('//.sc//,  lH()(i.  H3.  A.  Del  K'io,  "Report  on  the  Rapjialianiioci* 
Gold  Mine,  Virginia,"  1824.  K.  W.  Johnson,  "On  the  (Jiarnett  Gold  ]\lini', 
Virginia,"  1S.')2.  \V.  R.  .Johnson,  "  Some  Observations  on  the  Gold  I'm 
mat  ions  of  ]Mary  land,  ^'irginia,  and  North  Carolina,"  Proe.  Ainer.  .bs.sf'r, 
Adv.  Sei.,  IH:<0,  IV.,  20.  M.  F.  :Maury,  "Notice  of  Gold  Veins  of  the 
United  States  "Sline,  near  Fredericksburg,  Va.,"  Ainer.  Jour.  Sei.,  i.. 
XXXll.,  325,  1837.  J.  H.  Morton,  "Gold  Mines  iu  Virginia,"  Eu(j.  and 
Min.  Jour.,  XXV.,  1878.  T.  Pollard,  on  (3old  iu  Virginia,  see  Locks 
"Gold:  Its  Occurrence  and  Extraction,"  1882,  183.  B.  Silliman,  "He 
marks  on  Some  of  the  Gold  Mines  and  on  Parts  of  the  Gold  Regions  of 
Virginia,"  Ainer.  Jour.  Sci.,  i.,  XXXIL,  9M,  18:i,  185   1837. 


GOLD  IN  UNITETt  STATES  AND  CANADA. 


383 


Maryland,  uot  far  from  Washington,'  and  a  few  indications  of 
f^old  have  heeu  mot  in  FtMinsylvania,"  New  Jersey,  New  York,' 
and  Massachusetts.'  In  the  metamorphosed  Cambrian  and 
Silurian  strata  of  Vermont  "(juite  serious  attention  has  been 
^iven  to  both  veins  and  gravels.  Gold-bearing  mispickel  is 
known  in  New  Hampshire,"  as  well  as  in  the  usual  quartz 
veins.  Some  attempts  at  washing  gravels  have  been  made  in 
Maine"  and  in  Rhode  Island  in  the  slates  and  gneisses  around 
the  great  intrusions  of  granite,  (quartz  veins  are  not  infreiiuent. 
Traces  of  gold  have  been  met. 

■i.i;j.OH.  Example  4")/;.  In  the  fundamental  complex  ('^.0-^.  17) 
north  of  the  iron  region  at  Ish})eming,  gold  occurs  at  the  Ropes 
mine  in  reticulations  of  pyritous  (juartz  and  country  rock  at  the 
contact  of  a  great  intrusion  of  peridotite  with  greenstone  schist. 
Other  less  developed  locations  are  on  tjuartz  veins  in  the  schists." 

2.13.00.  The  Raiuii  River  District.  This  includes  the 
country  adjacent  to  Rainy  Lake  and  the  Lake  of  the  Woods. 

'  S.  F.  Emmons,  "  Notes  on  the  Gold  Dejjosits  of  Montgomery  County, 
S\>\.r  Tnnis.  Amn:  Inst.  Min.  Eikj.,  XVIII.,  :«)(>,  ISitO,  See  also  W.  R 
.lolinson,  miller  Virginia  above,  and  likewise,  I'liilos.  May.,  XXXVl., 
n-l  1850,  and  Amer.  Jour.  Sci..  ii.,  IX.,  \2(). 

•  Eckfeldt,  "Discovery  of  (!ol(l  in  Phil;id('l]»liia  Clay,"  (Scents  to  en.  ft.). 
rroc.  Auicr.  Phil.  Soc,  VIII.,  27:5  ;  Amer.  Jour.  Sci.,  ii.,  XXXII.,  2!)7.  C. 
.M.  Wetlierill,  Note  in  Philos.  Mag.,  IV.,  1.50,  February,  IHo;},  and  in  Enl- 
iiKiun's  Jour,  fi'ir  prakt.  Cliein.,  LVIII.,  447  ;  Avier.  Jour.  Sci.,  ii.,  XIX., 
•v'!li). 

'  ,F.  (t.  Polde  and  John  Torrey,  "Gold  in  Rhinebeck,  Dutchess  County, " 
Amrr.  Jour.  Sci..  ii..  XLVII.,  liii).  See  R.  W.  RaynioTid,  "Tlie  New  York 
Mining  lyaw,"  TraiiK.  Aiiicr.  Tiisf.  Min.  Eixj.,  XVI.,  770. 

'  J.  N.  Blake,  "(ioldat  Dedlium,  ilass.,"  Amer.  Jour.  Sci.,  ii.,  II.,  411). 

'  The  subject  is  taken  up  in  the  Report  of  the  Geological  Survcjf  of  Ver- 
nioitt.  Vol.  II.,  ^4'.}.  lH(il,  and  a  map  sliowing  the  liistriliution  of  auriferous 
Kniv(!ls  is  given  in  Plate  I.  ().  P.  Hubbard  refers  to  (iold  in  \'eruu)iit  in 
Aiiicr.  Jour.  Sci.,  ii.,  XV.,  147. 

'  (Icdlogi/  of  Xciv  I  lamps]!  ire.  III.,  Part  V.,  p.  4,  1878.  II.  Wurtz,  Amer. 
•loin:  of  Milling.  S(>i)teiiil)er  15,  lS(iH. 

'  M.  E.  Watlswortli,  "  On  an  Occurrence  of  Gold  in  Maine  "  (in  a  quartz 
vein).  Bull.  Miis.  Comp.  Zool..  VII.,  No.  ;i,  p.  IHl.  May,  ISSl.  Harvard 
I'liir.  Bull..  .Tune,  ISSI,  p.  '.210.  Gold  gi-avels  liave  occasioned  .some  ex- 
citement on  the  Swift  River.     On  silver  in  Maine,  see  above,  ;2.O0.O4. 

"  C.  D.  Lawton,  Rep.  Mich.  Com.  of  Mineral  SiatiNtics,  1887,  p.  167. 
"The  New  Michigan  Cold  Field,"  Eng.  ami  Jh'n.  Join:.  September  23, 
"SHs,  p.  2'.i8.  M.  K.  Wadswortli,  Ann.  Hep.  Jlich.  State  Geologist,  issued 
Jiiimary,  1892,  p.  152. 


'  t 


Ill{lllll 


384 


KKMP'S  OIIK  DK POSITS. 


For  Hevoral  yofirsit  han  been  known  that  p>M  prospoctH  existed 
in  the  rej^iou  Ij'iny  alonj;  tiie  national  honndai'}',  in  and  north  nl' 
Minnesota.     Some  (dainiH  in  tlie  Jiainy  Lake  region  are  in  Min- 
nesota, but  the  greater   part  of  the   productive  or  pronpective 
country  lies  in  Ontario.     The  geology  of  the  regions  arotuid 
Kainy  Lake  ban  been  mapped  in  detail  by  A.  C.  LaWHon,  but 
that  around  the  Lake  of  the  Woods  has  not  yet  received  tiie 
name  complete  study.     Near  Kainy  Lake  the  geology  involves 
Laureutian  granites  and  gneisses;  mica  schists  and  fine  grained 
micaceous  gneiss    of  the  Coutchiching;  greenish  and  sericitio 
schist,  conglomerate,  graywackes,  etc.,  of  the  Keewatin,  and 
minor  developments  of  eruptives,  such  as  gabbros  and  dialiaye 
<likes.     The  ore  deposits  em  brace  segregated  veins,  fissure  veins 
and  fahlbauds,  according  to  H.  V.  Winchell  and  U.  S.  Grant,  ;;« 
cited   below.     The  segregated  veins  are  series  of   overlapjiing 
lenses  of  auriferous  (luartz,  with  py rite,  that,  although  of  no  great 
individual  size,   may  yet  form  a  somewhat  extended  deposit. 
They  occur  in  the  schists  of  the  Coutchiching  and  Keewatin,  and 
run  parallel  to  the  schistosity,  apparently  along  lines  of  local 
faulting.     Tlie  fissure  veins  are  most  pronormced  in  granite. 
The3^  are  individually  larger  than  the  first  type,  and  when  in 
foliated  rocks,  they  cut  the  schistosity  at  a  greater  or  less  angle. 
The  fahlbands  are  belts  of  foliated  rock  impregnated  with  kiiI- 
pliides.     Sulphides  of  iron,  copper,  zinc,  lead,  cobalt  and  silver 
are  known.     The  mines  of  Rai.    "  Lake  have  not  yet  assumed 
great  economic  importance,  but  are  of  promise.' 

2.13.10.  The  Lake  of  the  Woods  lies  northwest  from  Rainy 
Lake  and  entirely  within  the  limits  of  Ontario.  The  geolo^'i- 
cal  relations  are  much  the  same  as  those  of  the  latter.  Keewatin 
schists  are  infolded  in  Laurentian  granite  and  gneiss,  and  all 

'  A.  P.  Coleman,  "Abstract  of  ii  Report  to  the  Bureau  of  Mines  o( 
Ontario,"  En(f.  and  Mhi  Jour.,  December  3'2,  isy4,  .IHl.  "Clastic  llunm- 
ian  lioi'ks  of  Western  Ontario."  Bull.  Chnl.  Sac.  Amer.,  IX.,  !22;{,  1S!(S.  A, 
C.  Lawson,  "  ReiK>rt  on  tlie  Geology  of  the  Rainy  Lake  Region,"  ^'co/. 
Snnrj/  of  CitnmJa.  Aim.  Rrp..  1H87,  Part  F.  W.  H.  .^lerritt.  "The  Or- 
currence  of  Cold  Ores  in  tlie  Rainy  River  District.  Ontario,  '  7'm«.s'.  Anicr. 
Inst.  Min.  Eng.,  XXVI.,  858,  189(5.  W.  W.  Taylor,  "Ceology  and  Clmr 
acter  of  the  Rainy  Lake  Gold  District,"  ^»f/.  and  Miii.  Jour.,  DecemliiT 
1,  18!)4,  p.  rM).  U.  V.  Winchell  and  U.  S.  Grant,  "  Preliminary  Reiwrt  on 
the  Rainy  Lake  Gold  Region,"  Gcol.  Survey  of  Minn.,  XXIIl.  Ann.  licp., 
35,  105,  18J),5. 


GOLD  IN   UNIT K I)  STATES  AND  CANADA. 


385 


are  pierced  by  later  granite.  There  is  alno  a  very  cousiderable 
development  of  volcanic  rocks,  both  tnffH  and  flows,  now  more 
or  leHH  schistose.  Considerable  alteration  has  taken  place  in 
,:\\,  and  as  emphasized  by  W.  H.  Mcrritt,  secondary  minerals 
have  been  developed.  The  veins  are  found  in  the  schists,  but 
lavcr  the  portions  near  the  contact  with  the  granite  or  gneiss. 
The  |.'old  is  free  and  in  the  usual  sulphides,  and  in  some  veins 
there  is  considerable  molvbdenite.  Bismuthinite  is  also  re- 
ported.  Several  mines  have  reached  a  productive  stage,  and 
there  are  man}'  prospects.' 

2.i;5.11.  In  the  summer  of  1X07  indications  of  gold  were 
also  met  in  the  region  near  Michipicoten  River,  which  enters 
Lake  Superior  on  its  northeastern  coast.  Auriferous  quartz 
veins,  some  of  which  have  yielded  good  assays,  have  been 
located.     The  richest  are  near  Wawa  Lake.* 


ALASKA    AND   THE   CANADIAN   NORTHWEST. 

'^.13. 12.  Croloffj/. — Onr  knowledge  of  the  geology  of  Alaska 
is  still  far  from  complete,  when  the  entire  territory  is  consid- 
ered, but  it  has  been  greatly  amplified  within  the  last  few  years 
by  the  mining  explorations,  and  the  governmental  expeditions 
sent  out  as  a  result  of  them.  The  observations  thus  far  re- 
corded deal  chietly  with  the  coast,  and  with  the  drainage  basin 
tif  the  Yukon,  or  with  the  passes  which  penetrate  to  its  upper 
waters.  Mesozoic  rocks  extend  north  from  Washington  and 
A'aucouver  so  as  to  appear  in  Queen  Charlotte's  Island,  and  at 
H  few  points  in  the  Aleutian  Islands.  Tertiary  beds  occur 
over  a  wide  area,  and  have  been  located  at  numerous  points, 
lioth  on  the  mainland  and  among  the  islands.  Metamorphic 
locks  from  both  igneous  and  sedimentary  originals,  unaltered 
plutonic  tj'pes  and  intruded  dikes,  and  more  recent  effusive  vol- 


'  E.  Coste,  "  Rei)ort  on  the  (itold  Mines  of  the  Lake  of  tlie  Woods,"  Oeol. 
SKiTcif  Canada,  1882-84,  Kep.  K.  W.  Douglass.  "  Tlie  Lake  of  tlie  Woods 
District,"  Eikj.  and  Min.  Jour.,  February  l(i,  ISi)'),  j).  lo^.  W.  IL  ^[erritt, 
'  Tlie  Ofcrurrence  of  (iold  Ores  in  the  Kainy  River  District,  Ontario," 
Tvam.  Amer.  luHt.  Min  Entj.,  XXVI.,  85:1  1S9(i.  T.  A.  Rickard,  "  The 
1  ake  of  the  Woo.lstioid  Field,  "  hUm,  July  ;?,  18!>r,  p.  T).  R.  H.  Williams, 
■  The  Lake  of  the  Woods  District,"  Idem,  July  2S,  18!(4,  p.  75. 

'  .1.  T.  Donald,  '  '"'a.nada's  Newest  Gold  Field,"  Enij.  and  Min.  Jour., 
}<cptember  25,  189"         '<"0. 


"^■a 


886 


KKMl'S  OUH   /ih/'OSlTS. 


m 


PI.KISrOCHNK 
UOSTI.Y  l.ACUr^TlUNK 

SII.TS  NKdCKNK 


mi 


KOl'h;  vi:  MISSION  CKKKK 

KKNAI  SKKIKS  SKllllCS 

EiB       mm 

Tanana  Itlreri 


TAIIK  VNIIIT 
SKIIIKS 

E2] 


HAM  I'M   I' 
SKIill- 


SECTION  ON  lilNR  A- A 

Fid.  150.— Western  hdfof  (Heohgienl  map  of  the  Yukon  Gold  Belt  and 
adjacent  ret/ions.     (See  Fia.  151.) 


UI  Belt  and 


NATURAL  SCALE 

Fto.  151. — Kdstfrn  half  of  Grolnrfirnl  map  of  tJie   Ynl-on  Gold  Belt,  and  ad- 
jacent reijions,  ri'j>riiihir<(t  in  iine  irork  euid  kIujIiIIji  reduced  from  a 
colored  rndp  hi/  J.  K.  Spiirr,  XV /If.  Ann.  licp.  V.  S.  Qeol. 
Suroe]/,  I'.irt  III.,  Plate  XXXVIfL,  p.  252. 


38b 


KEMP'S  OliE  DEPOSITS. 


canics,  some  from  vents  still  active,  are  the  chief  components 
of  the  coastal  exposures. 

In  the  interior,  in  the  Yukon  basin,  and  especially  in 
the  area  near  the  international  boundary,  the  general 
stratigraphy  has  been  more  systematically  studied,  and 
may  now  be  outlined,  since  the  valuable  paper  of  J.  E.  Spurr 
has  become  available.  In  order  to  make  the  geology  of  this 
important  region  clear,  the  colored  '•econnaissance  map  of  Spurr 
is  reproduced  in  Figs.  lAO  and  151,  in  line  work  on  a  somewhat 
smaller  scale  than  thj  original,  and  in  it  the  results  of  his  ex- 
])lorations.  as  well  as  those  of  Dall,  Hayes,  Geo.  Dawson, 
McOonnell  and  others,  are  set  forth. 

Thf  oldest  formation  is  granite,  of  massive  or  more  rarely 
gneissoid  structure.  It  consists  chiefly  of  quartz,  orthoclane, 
microcline,  plagioclase  and  biotite,  with  accessory  muscovite, 
calcite,  epidote,  garnet,  hematite,  kaolinite,  pyrite  and  chlorite. 
It  is  most  extensively  exposed  south  of  the  Yukon  basin,  but 
outcrops  to  the  north  in  sufficient  amount  to  show  that  the  lati'V 
formations  rest  upon  it.  It  is  considered  Archean,  and  is 
called  the  Basal  Granite.  Immediatel}-  above  it  is  a  series  cf 
quartz-schists,  estimated  at  25,000  feet  in  thickness,  and  called 
the  Birch  Creek  series.  Many  quartz  veins  occur  in  it,  chiefly 
parallel  with  the  schistositj'.  The  Birch  Creek  series  passes 
into  the  Forty-Mile  series,  which  consists  of  micaceous  and 
hornblendic  schists  with  interbedded  crj'stalline  limestones. 
The  Forty-Mile  series  likewise  contains  many  quartz  veins,  and 
both  it  and  the  Birch  Creek  series  are  penetrated  by  many 
dikes  of  granite  and  diorite.  In  geologic  succession  the  Ram- 
part series  follows,  and  exhibits  a  heavy  d'oss-section  and  wide 
areal  distribution  of  diabases,  and  associated  tuffs,  with  some 
impure  limestones  and  shales.  The  Rampart  series  is  probably 
pre- Devonian,  as  is  shown  by  the  fossils  in  the  next  overlyii!-,' 
series,  and  the  Forty-Mile  and  Birch  Creek  series  are  still 
older,  but  a'l  are  uncertain  in  their  taxonomic  relations  except 
for  this  approximate  determination.  Quartz  veins  are  also 
present  in  the  Rampart  series.  The  Tahkandit  series  of  whi<'> 
and  gray  limestones  with  alternations  of  carbonaceous  shal  s 
and  conglomerates  follows  next  ibove.  It  is  known  from  fossils 
to  contain  some  Upper  Carboniferous  beds  and  probably  also 
embraces  others  of  Devonian  age.     Upon  it  rests  the  Missieu 


OOLD  IN  UNITED  STATES  AND  CANADA. 


389 


Creek  series  of  black,  calcareous  and  feldspatliic  shales  and 
thin  beds  of  impure  limestone,  and  gray  sandstone.  They  are 
known  to  be  Lower  Cretaceous.  The  Kenai  series  succeeds 
with  its  fresh- water  sediments  and  coal  sean)s  of  Eocene  age. 
N" eocene  deposits  follow  and  embrace  the  Nulato  sandstones, 
the  Twelve-mile  beds  of  gravels  and  lignites,  the  Porcupine 
lieds  of  sands,  clays  and  conglomerates,  and  the  Palisades  con- 
glomerates with  the  bones  of  huge,  extinct  vertebrates.  The 
Y'ukon  silts  are  Pleistocene  and  constitute  a  vast  area  of 
;tbandoned  lake-bottoms  along  the  middle  Yukon.  Eruptive 
liasalt  is  also  known,  but  in  connection  with  the  gold,  the  Basal 
granite,  the  Birch  Creek,  Forty-Mile  and  Rampart  series  and 
the  recent  gravels  derived  from  them  are  of  chief  interest. 

In  its  topographic  character  the  interior  is  largely  a  great, 
dissected  plateau  so  far  as  known,  with  rugged  and  uneven 
topography  on  a  minor  scale.  The  i-anges  of  mountains 
are  chielly  developed  near  the  coast.  The  surface  of  the 
interior  plateau  and  the  talus  slopes  are  covered  by  a  heavy 
mantle  of  moss,  called  a  tundra,  whose  roots,  at  a  depth  of  a 
foot  or  two,  are  frozen  in  perpetual  ice.  This  hides  the  geol- 
ogy, and  makes  exploration  ditlHcult  and  fraught  with  great 
hardship.  Along  the  streams  dense  thickets  of  alder  and 
.spruce,  and  in  the  glaciated  regions,  the  drift,  all  hide  "the 
i-ocks.* 

'  "Alaska  as  a  Miuing  Territory,"  E)i<j.  aud  Min.  Jour..  June  37,  1885, 
1'.  444.  "Jlineral  and  A<j,rifu!tural  Wealth  of  Alaska."  Emj.  and  Min. 
■huir.,  August  24,  ISST,  p.  \;J4.  (1.  F.  Becker,  '•Reoounaissjinc-e  of  tlie(Jold 
Field-s  of  Southern  Ala.ska.  with  some  Notes  on  Oeneral  tieology,"  XVIII. 
.\ini.  Ei-p.  U.  S.  Geol.  Snnwij.  Part  III.,  p.  7.  Rec.  T.  A,  Blake,  "Re- 
port on  tiie  Geology  of  Alaskii,  "  E.v.  Doc,  No.  ITT,  Fortieth  Congre.ss.  New 
Scries,  p.  314,  Washington,  1S()S.  W.  P.  Blake,  "tieographieal  Notes  upon 
h'lissian-Anierica  and  the  Stiekeeu  River;"  Reixjrt  addressed  to  t'.e  Sec- 
ntary  of  State,  Wa.shington,  !8()().  H.  P.  Cashing,  "Notes  on  tiie  Areal 
(^■•ohgy   of  Glacier  Bay,    Alaska,"   Trnn.'i.  N.  Y.  Avad.  of  Sci..   XV.,  34. 

Xotes  on  the  Muir  (Glacier  Region  audits  (Jeology,"  ..4n(('/'.  (icoL,  Oeto- 
Iter  1891,  2l)T.  W.  H.  Dall,  '•  F.\i)loraiions  in  Alaska,"  .1  ;;;(■/•.  Jo,*;-,  .Sc/.. 
ii.,  XLV.,  96.  Ree.  "Notes  on  Alaska  and  the  Vicinity  of  Bering 
Straits,"  Ibid.,  Hi.,  XXI.  KU.  "  Notes  on  Alaska  Tertiary  De|Kisits.  Geologi- 
(•;d  Section  of  the  Slunnagin  Islands,'  Ibid.,  iii.,  XXIV.,  (iT.  "Ala.ska  and 
it -i  Resources,"  Washington,  IMTo.  Rt;c.  "  Glaciation  in  Alaska."  liidl. 
I'hil.  Soc,  Vol.  VI.,  p.  :W.  Washington,  1884.  G.  M.  Dawson,  "Report on 
the  Yukon  District  in  IMh?,"  Geol.  Snrreij  of  Canada,  188T-88,  Vol.  III., 
Part  B,  pp.  1  IB.  KB.  ir)4B-ir)(SB.     H.  W  .Elliot,  "Our  Arctic  Province.s," 


Iffl' 


390 


KEMP'S  OltE  DEPOSITS. 


2.13.1:].  Example  :]8.  (See  above,  2.00.01.)  Douglass 
Islautl.  A  dike  of  shattered  albite-diorite  (sodium-syenite) 
iiiipveguated  with  gold-bearing  pyrite.  The  largest  and  most 
productive  of  the  mines  along  the  coast  of  Alaska  is  the 
Alaska-Treadwell  and  its  affiliated  properties,  on  Douglass 
Island,  about  two  miles  southeast  from  the  town  of  Juneau. 
The  ore  body  is  peculiar  and  interesting,  and  while  the  grade 
of  the  ore  is  low,  the  conditions  for  treating  it  cheaply,  and  <iii 
a  large  scale,  are  very  favorable.  The  geological  relations 
have  recently  been  described  by  G.  F.  Becker,  ujion  whose 
paper  the  following  outline  is  based. 

The  countrj'  rock  is  a  carbonaceous  slate  of  uncertain  but 
possible  Triassic  age.  Its  sedimentary  bedding  has  been 
destroyed,  but  its  cleavage  strikes  N.  50  E.,  and  dips  southeast. 
After  the  metamorphism  to  slate,  it  was  penetrated  by  an  irregu- 
lar dike,  which  is  4r)()  feet  and  less  wide,  and  is  considerably  split 
up  by  horses  of  country  rock.     The  dike  rock  is  a  peculiar  one, 


p.  163,  New  York,  1887.     G.  W.  (Tarside.  '■  Miueral  Resources  of  Sontlieast 
Alaska,"  Trana.  Amer.  Innt.  Min.  Eiuj.,  XXL,  SI.").     E.  J.  (ilave,  "Pionpe-r 
Pack-liorses  in  Alaska,"  The  Century,  8ei)tpml)er  and  October,  181)2.     V. 
W.  Hayes,  "An   Expedition   through  the    Yukon    District,"   Nut.  Gi'ini. 
]\huj.,    IV.,    IIT-KIO,    1S<)2.     Augelo    Heilprin.     'Alaska  and   the    Klon 
dike,"  New  York,  ISSM).     R.  G.  McConnell,  "Glacial  Features  of  Parts  of 
the  Yukon  and  .Mackenzie  Basins,"  (Icol.  Soc.  of  Amer.,  I.,  p.  040.     H.  1". 
Reid,    "CHacier  Bay  and  its  (Jlaciers,"  AT/.  Aun.  Rep.  Dii:  U.S.  Gcul. 
Survey,  ISJUi,  I..  421.     I.  C.   Rus.sell,  "The  Surface  Geology  -f  Alaska, 
Geol.  Soc.  of  Amer.,  I.,  p.  iff).     "An  Expedition  to  l\It.  St.  Elias.  Alaska  ' 
Nat.  Geogr.  Mag.,  III.,  5:?.  204,   18!)!.     "  Mt.  St.  Elias  an<l  its  Glaciers.  ' 
Amer.  Jour.  Set.,  starch,  1802,  1(U).     "Origin  of  the  Gravel  Deposits  l)c 
neath  the  Muir  (Jlacier,   Alaska,"   Amer.   Geol.,  March,  1892,  180.     J.  E. 
Si)urr  and  H.  B  Goodrich,  "(Jeology  of  the  Yukon  Gold  District."  XVIII. 
A)ni.   Ri'p.    U.  S.    Geol.   Survey,   I'art   III.,  87.     Rec.     E.    R.   Skidnioiv. 
"Alaska,"  Rep.  Director  of  the  Mint,  188:5,  p.  17,  and  1884,  p.  17.     J.  Stnii- 
ley-Brown.  "Aiu'iferous  Sands  at  Yakutat  Bay.  Alaska,"  Nat.  Gcogr.  Maij  . 
Vol.  III.,  l!»rt.  18!)1.     J.  J.  Stevenson,  "Some  Notes  on  Southeastern  Alasl^a 
and   its  People."   Scotti.sh   Gcogr.  Mag.,  February,   1893.     J.  B.  Tyrrell, 
'Glacial  Phenon:   iia  in  the  Canadian  Yukon  District," /?»//.  <^?C()/.  .S'l"'. 
Amer.,  X.,  193,  1899.     G.  II.  Williams,  "Notes  on  Some  Eruptive  Rocks 
from  Alaska,"  Nat.  Geogr.  Mag.,  IV.,  03. 

Note. — The  Bulletin   of  the  Boston  Public  Library  f  jr  Se|ttember,  1S!i: 
p.  ir)3.  has  a  <'om])lete  bibliogra))hy  of  the  Yukon  region  up  to  tiiat  dai'-. 
Tu  1H!»!),  the  L'.  S.  Geological  Survey  i.ssue.l  a   pamphlet  entitled,  "Ma|'s 
and  Descriptions  of  Routes  of  Exploration  in  Alaska,"  together  with  i' 
valuable  series  of  maps. 


GOLD  IN   UNITED  STATES  AND  CANADA. 


391 


ami  is,  as  a  rule,  now  much  altered,  but  iu  the  freshest  material 
available,  it  is  almost  entirely  albite.  It  contains  small 
amounts  of  augite,  hornblende,  biotite  and  a  few  plagioclases 
other  than  albite.  Secondary  quartz  is  abundant.  After  the 
intrusion  of  the  diorite,  a  gabbro  dike,  with  some  tendencies 
toward  diabase  iu  its  texture,  penetrated  along  the  northeast  side 
of  the  diorite,  being  sometimes  entirely  in  the  slate.  The 
gabbro  is  chiefly  augite  and  plagioclase.  and  carries  no  value 
in  gold  that  is  practically  serious.  After  the  intrusion  of  the 
gabbro  a  narrow  dike  of  analcite-  basalt  4  to  (»  feet  wide  cut  all  the 
other  rocks.  Before  its  ^"ntrusiou,  the  others,  and  especially  the 
albite-diorite,  suffered  severely  from  crushing,  the  latter  being 
cracked  by  series  of  planes  at  right  angles  with  each  other,  and 
inclined  at  4/)°  to  the  hori/on.  Along  these  cnicks  the 
mineralization  has  taken  place,  and  quar'^ '  calcite,  gold-bearing 
pyrite,  with  r.-e  chalcopyrite,  mispickei,  blende  and  galena 
entered.  The  analcite-basalt  accompanied  or  closely  followed 
the  mineralization.  During  the  latter  t,he  ferromagnesian  sili- 
cates of  the  original  albite-diorite  were  replaced  by  the  pyrite.^ 

F.  D.  Adams  has  detected  metallic  gold  in  the  midst  of  the 
jjvrite  in  a  thin  section  of  the  oi^. 

South  from  the  Treadwell  mine  is  an  unworked  claim,  and 
then  tne  Mexican,  which  is  operated  by  the  same  parties  as  the 
Treadwell. 

In  connection  with  the  petrography  of  the  Treadwell  ore,  it 
is  interesting  to  remark  that  num.erous  dikes  of  albitic  rock 
occur  in  the  Sierras  of  California,  and  aie  known  to  be  gold- 
bcfiring  in  a  number  of  instances." 

2.13.14.  The  other  mines  that  have  been  developed  along  the 
coastal  region  are  not  numerous  as  yet.  Some  three  miles  east 
of  Juneau  there  is,  in  tiie  midst  of  the  mountains,  a  small 
abandoned  lake  basin  called  Silver  Bow  basin,  whose  sands  are 

'  F*'.  1).  Adiiiiis,  "On  tlie  IMicroscopical  riiamcter  of  the  Ore  of  the 
Treiuhvell  Mine,  Ahiska,  "  Amn:  dcol.,  AuKust.  ISSit.  p.  SS.  (}.  F.  Bei'ker, 
"  ReconiiJiissjinoe  of  the  (x'  1  Fields  of  Soiitliern  Aliiskii,  with  Honie  Notes 
on  tlie  General  OeoloRV,"  XVIII.  Ann.  Rep.  Dii:  U.  S.  Gcol.  Sitnri/.Vurt 
111.,  p.  1.  Keo.  (}.  M.  Dawson,  "  Notes  on  tiie  Ore  Deposits  of  the  Tread- 
v.cll  Mine,  Alaska,"  >rlH(.'r.  (icol ,  August,  1889,  p.  84.  Min.  and  Sci. 
7Vf,s,s,  San  Francisco,  September  27,  October  4,  1884. 

"  Seell.  W.  Turner,  "  Heplacenient  Ore  Deposits  in  the  Sierms,"  Join:  of 
Gcol.,  May-June,  IS'.tl).  ;{M!).     ('oniiMire  al.so  paragraph  12. 12.20. 


392 


KEMP'S  OIIK  n/^: POSITS. 


gold-bearing  to  a  degree  that;  admits  of  prcfltible  hydraulickiug. 
In  the  surrounding  mountains  of  schists  there  are  a  few  veins 
that  have  received  attention  at  the  Bennet,  the  Lane  and  Hay- 
ward  and  the  Taku  mines.  Over  the  divide  to  tlie  south,  in 
the  drainage  of  Siieep  Creek  basin,  are  several  other  veins  iu 
schists.  They  carry  silver-bearing  sulphides,  with  minor  gold 
values.  The  country  rtx;k  is  schist,  carbonaceous  and  mica- 
ceous, with  gabbro  dikes. 

2.13.15.     At  Sunulum   Bay  there  are  slates,  which  are  pene- 
trated  by  granitic  dikes.     They  also  contain  lenses  of  quartz 


Map  of  the 

Juneau 

Mining  District 

of  Southeast  Alaska. 

I89S. 

aernl* 


n 


i''iu.  1")"2.  —  Map  of  tht'  Jnuciin  iiihiiii<i  dixtrift,  mntlndxt  Aiaxka.     After 

G.  F.  Becker,  X  Vfff.  Ann.  Wp.  Dir.  U.  S.  Oeol.  Survey, 

Part  III,  Plate  X  VI.,  reduced. 


with  sulphides  carrying  gold  and  silver.  Near  Berner's  Bay 
the  diorite  has  quartz  veins  with  sulphides,  and  at  Funters 
Bay,  in  the  Admiralty  Islands,  schists  derived  from  diabasi' 
hold  veins  io  cross-fissures.  Pyrite  and  pyrrhotite  occur  in 
a  gangue  of  quartz.  Near  Sitka  veins  with  low  grade  ores 
have  been  found  in  a  pyroclastic  diorite,  and  on  Kadiak 
Island  there  are  some  prospects,  as  well  as  guld-b»aring  beach 
sands.  Next,  however,  after  the  mines  on  Douglass  Island,  tlio 
largest   on  the   Alaskan    coast   is  the   Apollo  mine  on  Unj^a 


00 LD  IN  UNITED  STATES  AND  CANADA, 


39iJ 


Island.  The  wall  rock  is  andesite,  probably  post-Miocene. 
The  ores  are  free  gold,  pyrite,  galena,  zincblende,  cbalcopyrite, 
aud  some  uative  copper,  in  a  large  chute  along  a  zone  of  frac- 
ture. 

•^.13.1(i.  The  Yukon  Basin.  The  greatest  interest,  so  far  as 
the  mineral  resources  of  Alaska  and  the  Northwest  Territory  of 
C.mada  are  concerned,  centers  around  the  gold  placers  of  the 
^'ukon  basin.  So  far  as  yet  developed  the  richest  lie  in  Cana- 
dian territory,  and  from  these  the  chief  production  has  thus  far 
been  obtained,  but  the  older  workings  are  on  the  American 
side,  and  some  gold  is  annually  obtained  from  them  yet.  The 
gold  occurs  in  two  different  kinds  of  gravels.  Ihe  ore  lies  on 
the  bed-rock  beneath  the  courses  of  the  smaller  streams  and 
their  tributary  gulches,  which  latter  are  locally  called  "pups." 
Above  the  pay-streak  lies  a  variable  thickness  of  barren,  frozen 
gravel,  which  is  overlain  by  peaty  muck.  The  pay-streak  is 
exjiosed  by  thawing  out  a  pit  in  the  frozen  gravel  by  means  of 
fires  and  heated  stones,  so  that  it  can  be  excavated  and  stacked 
lip  until  the  warm  season  affords  water  for  panning,  cradling, 
01  more  rarely,  sluicing.  Except  that  the  ground  is  frozen  the 
placers  do  not  differ  from  those  already  fully  outlined. 

•.'.115.17.  The  second  variety  of  gravels  is  the  "bench'* 
gravel,  which  occurs  on  the  sides  of  the  valleys  above  the  pres- 
ent stream  hottoms.  They  are  regarded  by  Tyrrell  as  the 
tormina!  moraines  of  small  glaciers,  which  came  but  a  compar- 
atively short  distance  down  the  hillsides  and  st  ipped. 

■.'.13.18.  The  source  of  the  gold  appears  to  have  been  the 
qn  irtz  veins  in  the  Birch  Creek,  Forty-Mile  and  Rampart 
series,  as  described  under  paragraph  '^.13.13.  The  veins  seem 
to  have  been  ind.  vidually  small,  for  thus  far  no  one  has  yet 
iroved  available  for  deep  mining.  A  few  have  been  proved  to 
aciually  contain  gold,  and  have  thus  given  real  as  well  as 
theoretical  ground  for  the  above  inference  The  veins  chiefly 
mil  parallel  with  the  foliation,  although  some  fissure  veins,  that 
cross  it,  are  known.  Assays,  so  far  as  recorded,  while  they 
cleiuonstrrite  the  presence  of  gold,  do  not  indicate  great  richness. 
(Citations of  the  litei-ature  will  be  found  under  'i.  13.  \-l.) 

■.*.13.1!).  South  of  the  headwaters  of  the  Yukon,  and  after 
all  interval  of  barren  territory,  so  far  as  known,  lies  the  Cassiar 
district,  which  is  reached  from  the  coast   ria  Wrangell  and 


394 


KKMP'S  ORE  DEPOSITS. 


the  Stickeeu  River.  From  the  coast  inland  schistose  rocks, 
with  a  few  limestones  and  extensive  intrusions  of  granite  form 
the  oldest  rocks,  but  there  are  many  sheets  of  basalt  of  most 
interesting  character,  especially  near  the  head  of  navigation  on 
the  Stickeen  River.  The  chief  gold  discoveries  have  been 
made  in  the  past  in  the  drainage  area  of  Dease  Lake.  The 
gold  occurred  in  stream  gravels,  but  the  heavy  glacial  deposits 
have  at  times  buried  them  under  a  great  amount  of  later  and 
barren  debris.  One  of  the  routes  to  the  Klondike  passes 
through  the  region/ 

2.13."^0.  In  the  drainage  area  of  the  Columbia  River  just 
north  of  the  international  boundar}',  and  lying  between  it  ;ind 
the  line  of  the  Canadian  Pacific  railway,  important  develop- 
ments in  mining  have  been  made  in  recent  years.  The  region 
is  mountainous  and  rugged.  The  Columbia  and  its  tributary, 
the  Kootenay,  into  which  flows  the  Slocan,  have  their  courses 
largely  formed  by  long  and  relatively  narrow  lakes,  which, 
being  navigable,  have  greatly  aided  in  the  development  of  the 
mines.  The  Columbia  passes  through  Upper  and  Lower  Arrow 
Lake;  the  Slocan  heads  in  Slocan  Lake,  lying  to  the  east;  and 
the  Kootenay  drains  the  waters  of  Kootenay  Lake  still  further 
east.  All  these  lie  in  long  north  and  south  valleys,  and  into 
them  the  smaller  streams  discbarge  from  the  mountains  lying 
east  and  west.  In  the  valleys,  and  on  the  mountain  slopes 
along  these  creeks  the  veins  have  been  located.  The  Slocan 
district  extends  from  west  of  Lower  Arrow  Lake  eastward  be- 
yond Slocan  Lake;  the  Ainsworth  district  surrounds  Kootenay 
Lake;  the  Nelson  lies  along  the  Kootenay  River  between 
Kootenay  Lake  and  the  Columbia  River;  while  Trail  Creek 
embraces  both  banks  of  the  Columbia  as  it  leaves  Canada  and 
crosses  the  international  boundarj\ 

Dr.  Geo.  M.  Dawson"^  recognizes  on  Kootenay  Lake  and  on 
Adams  Lake  (which  latter  is  loO  miles  northward  of  the 
former)  the  following  series,  beginning  with  the  oMfst 
{Bull.  Geol.  Soc.  Amer.  IL,  108): 

'  G.  M.  Dawson,  Geol.  Suri-ej/  of  Cunada,  111.,  \Si<H,  Report  B.  K.  I>. 
Self,  " The Cassiiir  District,"  Eiuj.  aud  Min.Join:,  Fehniary  IH,  IS!)!),  JO.-). 

■•'  G.  M.  Dawson,  '  Report  on  a  Portion  of  tlie  West  Kootenay  Distiiot, 
British  Columbia," -Rp/>.  B.  Can.  Geol.  Surveif,  IV..  18H8-HS).  Rec.  'Note 
on  the  (>e> (logical  Structure  of  the  Selkirk  Range,  '  Bull.  Geol.  Soc.  Ann'i:, 
II.,  ll'M,  isiil. 


GOLD  IS   UNITED  STATES  AND  CANADA. 


395 


1.  The  Shnswap  series.  Mica  schists,  gneisses  and  marbles. 
Archeau. 

•I.  The  Nisconlith  series.  Black  shaly  or  schistose  argillite, 
with  some  limestone.     Cambrian. 

;{.  The  Adams  Lake  series.  Gray  and  greenish  schists. 
Cambrian  and  Silurian. 

Above  these  are  limestones,  argillites  and  schists. 

W.  A.  Carlyle,'  in  the  report  cited  below,  mentions  above 
the  Nisconlith  series  in  the  Kootenay  region. 

15.  The  Kaslo  schists,  comprising  a  series  of  greenish,  proba- 
bly diabasic  schists  interbedded  with  some  slates  or  dark  argil- 
lites, and  limestones. 

1.  The  Slocan  slates,  a  series  of  dark  shales  and  slates,  with 
limestones  and  calcareous  cpiart/ites.  {Bulletin  Bureau  of 
Minf'S,  p.  45.) 

In  addition  to  the  stratified  rocks  there  are  vast  intrusions  of 
i;niLiite  regarded  as  later,  and  also  many,  more  basic  rocks,  such 
as  porphyrite,  diabase  and  gabbro,  which  are  often  intimately 
associated  with  the  ore  bodies. 

•*.  1  o.  -U .  In  the  Slocan  district,  W.  A.  Carlyle  has  recognized 
fdur  kinds  of  veins,  according  to  the  variety  of  ores  furnished, 
viz. :  (I)  Those  with  argentiferous  galena,  blende  and  some 
tt'trahedrite  in  a  gangue  of  quartz  and  siderite.  They  cut  strati- 
fied rocks,  dikes  and  granite  in  one  place  and  another.  Gold 
values  are  known  but  are  not  of  great  moment.  These  veins 
ait'  the  chief  ones  of  the  region.  {2)  Veins  of  argentiferous 
tehahedrite,  jamesonite  and  silver  minerals  in  cpiartz  gangue  in 
granite  and  stratified  rocks,  but  not  numennis.  (;5)  Veins  in 
jiianite  with  q'^artz  gangue,  carrying  argentite,  native  silver 
ami  gold.  (4)  Gold  quartz  veins  in  granite.  (Bulletin  III.,  pp. 
4ii  48.)  In  the  Ainsw^orth  district  all  t!ie  geological  series  are 
Tiiet,  and  any  one  may  be  the  wall  rock  of  a  vein.  The  com- 
mon gangue-minerals  i.^e  quartz  and  calcite,  and  the  ores  are 
f'ilver-bearing  galena,  with  some  blende;  or  pyrites;  or  silver 
minerals  with  more  or  less  of  the  other  sulphides,  or  of  tetrahe- 
(Inte  with  them.     In  the  Nelson  district  the  rocks  and  the  ores 


'  Win.  A.  Carlyle,  "Report  on  Sloc-an,  Nelson  and  Ainsworth  IMininpf 
Districts  in  West  Kootenay,  British  Columliia,"  Bull.  III..  Bureau  of 
.1///.'.s,  Victoria.  B.  C,  1S!)T.  .\nnnal  reports,  wit!)  maps,  are  i.ssued  by 
tile  I'rovincial  J\Iiner(ilo<ii.st.  Victoria.  B.  C. 


390 


KI'JMP'iS  QUE  DEPOSITS. 


m 


i 


are  somewhat  different  from  those  previously  described,  aid 
teud  to  resemble  the  ones  mined  at  Trail  Creek.  The  comitry 
rocks  are  porphyrites,  gabhros,  diabases  and  slates,  cut  by 
numerous  dikes.  The  ores  are  silver- bearing  sulphides  of  cop- 
per, especially  chalcopyrite,  and  the  common  associate  of  tlie 
latter  in  rocks  of  this  character,  pyrrhotite.  Gold  is  very  sul)- 
ordiuate.'  In  the  Trail  Creek  district  igneous  rocks  are  the 
chief  varieties  present.  There  is  an  older  series,  according'  to 
R.  G.  McConnell,''  of  porphyrites,  dial)ases,  gabhros,  tuffs,  and 
agglomerates,  with  occasional  patches  of  limestone,  which  aflortl 
son)e  fossils  of  probable  Carboniferous  affinities,  and  withscniie 
inchisious  in  the  igneous  rocks  of  Ijlack  slate.  Later  than  this 
igneous  series,  va  granite,  and  through  both,  dikes  of  h(  tii 
acidic  and  basic  rocks  have  been  intruded.  The  chief  ecoucmiic 
interest  centers  about  a  small  area  of  gabbro.  near  the  town  (if 
Rossland,  and  aoout  four  miles  long  by  one  mile  wide.  From  ;i 
gabbroof  granitoid  texture  in  the  central  mass,  it  passes  grjul- 
ually  into  a  rim  of  augite- and  uralite-jiorphyrites  and  diabiiM'. 
which  are  seldom  over  a  mile  across,  and  which  are  breccialid. 
At  or  near  the  contact  of  the  gabbro  and  the  porphyritic  border, 
are  met  the  ore  bodies.  The  ores  consist  of  auriferous  jiikI 
slightly  argentiferous  pjrrhotite  and  chalcop^-rite.  They  ;iio 
not  of  high  grade  as  a  rule,  the  gold  ranging  from  a  trace  to 
several  ounces,  and  the  silver  from  a  trace  to  four  or  live 
ounces.  A  little  nickel  and  still  less  cobalt  can  also  be  de- 
tected. Other  minerals  are  not  prominent;  molybdenite,  lii,u,li- 
ly  auriferous,  and  rarely  galena  and  blende  have  been  recorded. 
The  oxidized  zone  extends  but  a  few  feet  below  the  surface. 
It  is  still  somewhat  of  a  mooted  point  among  observers,  as  to 
whether  they  are  direct  crystallizations  from  the  codling 
magma;  or  secondary  segregations  from  the  enclosing  luisic 
walls;  or  replacements  along  lines  of  fissuring;  or  true  fis^Mire 
veins.  One  mine  and  another  seem  to  give  support  to  eacli  of 
these  views. 

The  geological  relations  strongly  suggest  those  of  Sudbury, 
later  describe<l   under  nickel,  and  also  those  of  many  nickel 

'  Tlie  fletails  of  these  distncts  are  taken  from  the  Hulletin  of  V> .  A. 
Carlylo,  previously  cited. 

"  H.  (!.  McC'oniiell,  "  PreHiniii;iry  Abstract,"  issued  in  Eosshnid  11'  i/,/// 
Mining,  Marcli  18,  ISUT,  a  local  paper. 


GOLD  IN   LXITKD  STATh'S  AND  CANADA. 


jjo: 


npoiiH  in  Norway  and  elHewhere  in  the  world.  The  question 
of  their  direct  origin  from  a  fused  and  cooling  magnia,  is  an 
important  and  interesting  one,  and  examinatitm  should  he  care- 
fully directed  toward  its  solution.  From  ohservations  made  in 
cdunection  with  recent  litigation  over  the  War  Eagle  claim, 
W.  Lindgrcn  reached  the  conclusion  that  the  ores  had  certainly 
ht'on  deposited  hy  replacement. 

•2.Vi.22.  Example  4oc.  Nova  Scotia.  The  southeastern 
])(irtion  of  Nova  Scotia,  exclusive  of  Cape  Breton  Island,  is 
cliiefly  composed  of  a  vast  series  of  metamorphosed,  fragmental 
deposits,  which  in  places  contain  gold-bearing  cpiartz  veins  of 
very  interesting  geological  relations.  As  a  rule,  the  veins  con- 
form to  the  betiding  of  the  wall-rocks  and  therefore  })reseut 
structural  problems,  exactly  like  those  of  thin  beds  in  a  folded 
aiiil,  to  some  extent,  faulted  sedimentarj'  series.  The  age  of 
the  sediments  is  thought  hy  some  to  be  Cambrian,  by  others 
j)re-Cambrian  or  Algonkian,  the  absence  of  assured  fossils 
ni.iking  the  question  an  open  one.  The  metamorphic  rocks 
are  penetrated  by  numerous,  great  intrusions  of  granite,  which 
constitute  no  inconsiderable  part  of  the  (),()()()  or  7,000  stjuare 
miles  that  the  area  embraces.  The  strata  have  been  divided 
!)}•  Ideologists  into  two  series.  The  upper,  approximately  :),0()0 
feet  thick,  consists  of  dark,  pyritous  slates,  with  some  beds  of 
(Hiartzite,  but  with  few  veins.  The  lower  series,  round  I}' 
estimated  at  8,000  feet,  has  a  much  larger  proportion  of  coarse 
sediments  and  em  braces  slates,  quartzites,  sandstones,  and  even 
conglomerates.  A  Lower  Carboniferous  conglomerate  is  known 
to  overlie  the  metamorphics,  and  to  contain  boulders  of  the  gold- 
bearing  quartz  veins,  so  that  the  mineralization  certainly  was 
of  earlier  date.  The  slates,  and  even  the  quartzites,  are  quite 
riehly  provided  wiih  pyrites,  and  are  known  to  carry  gold  even 
at  a  distance  from  the  veins.  There  is  reason  to  think  that 
this  gold  was  deposited  with  them  originally,  and  even  the 
pyrite  may  be  of  metamorphic  production,  from  materials  laid 
ilow  n  in  the  sediments.  The  presence  of  the  gold  and  pyrites 
iu  the  slates  has  an  important  bearing  on  the  methods  of 
enrichment  of  the  veins  and  the  direction  taken  by  the  gold- 
bearing  solutions. 

Inasmuch  as  the  larger  veins  lie  parallel  with  the  bedding 
ami  conform  to  the  folds  of  the  sediments,  it  is  evident  that  the 


qgp 


ei 


IS 

ex 

lie 


tio 


Soi 


ani.l)  IN   rXlTED  STATKS  AM)  r.\^^.\/)^. 


391) 


(luartz  was  deposited  in  thenj  before  tlie  foldinjjj  took  place.  J. 
E.  Woodtnan  states  that  the  original  tilliiif^  of  the  veins,  pre 
Htiinably  by  uprisiiifj^  solntions,  was  not  accompanied  by  tiie  in- 
tnulnction  of  niuoh  gold.  This  came  later,  during  the  nu^ta- 
niorphism,  and  probal)ly  was  contributed  by  the  pyritous  wall- 
nick.  The  lirst  and  major  folds  were  developed  with  axes 
riniuiug  approximately  east  and  west.  In  time  a  second 
compression  nearly  at  right  angles  to  the  first,  threw  these  folds 
into  a  north  and  south  series,  and  caiu-il  many  faults,  mostly 
reversed.  The  corrugations  produced  in  the  first  series  of  folds 
liy  tliese  later  ones,  gave  rise  to  the  so-called  "barrel  quartz," 
ami  as  the  latter  has  the  rej)utation  of  carrying  gocjd  values  in 
gold,  there  may  have  been  some  additional  enrichment  of  it 
(hiring  the  later  disturbances.  Probably  the  inti'usion  of  tho 
granite  followed  the  second  folding,  but  it  is  not  certain  that  it 
niiiy  not  have  preceded  the  first  upheavals.  The  second 
period  of  disturbance  produced  some  fissures,  which  were  filled 
at  Cow  ]jay  WMth  gold  (luartz.  In  the  suhsecjuent  history  of 
tlio  series,  a  jn-ouounced  northeastern  cleavage  was  develojied, 
and  some  small  faulting.  Erosion  has  been  severe,  and  has 
planed  oft'  the  <lomes  produced  b}'  the  cross- folding,  and  has 
largely  determined  the  location  and  extent  of  the  mining  dis- 
tricts. 

While  the  bedded  character  of  the  larger  veins  has  been 
emphasized,  it  must  be  appreciated  that  they  throw  oft'  stringers 
iutd  the  walls,  called  "angulars,"  and  that  jiarallel  ones  are 
counected  by  cross-veins.  Still,  except  at  Cow  Bay,  fissure 
veins  of  the  ordinary  type  are  not  often  met. 

The  ore  minerals  of  the  veins  are  free  gold,  gold-bearing 
pyrite,  mispickel,  and  rarely  galena  and  blende.  The  gangue 
is  chiefly  (piartz,  but  calcite  occurs  sporadically.  The  veins 
Hverage  less  than  a  foot  in  width,  but  may  be  several  feet  as  an 
exception.  They  favor  horizons  where  a  soft  rock,  usually  slate, 
lies  near  a  hard  one,  usually  quartzite.^ 

'  111  the  following  bibliography  the  citations  given  in  the  i)revious  edi- 
tioiiv  iire  greatly  eximnded  by  the  aid  of  Bidlctin  1:7  of  the  U.  S.  (reo- 
lii<,'i(  ,il  Survey  and  the  very  coin[)lete  list  in  the  palter  of  J.  PI  Woodman. 
\V.  .1  Anderson,  "(loid  Fieldsof  Nova  Scotia,"  Traus.  Lit.  and  Hint.  Sac, 
iifQihtHH'.  Part  II.,  pp.  -{."i-oO,  18()4.  L.  W.  Bailey,  "  Prehminary  Report  on 
Soutliwestern  Nova  Hcotia,"  Gcol  Surrci/  i'limtdu,  ISlCi-O;},  Peport  C^. 
'i.  F   Becker,  "Gold  Fields  of  the  Southern  Aitpalaehians,"  A'T7.  Aim. 


IMAGE  EVALUATION 
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KEMP'S  ORE  DEPOSITS. 


i!i 


2.13.23.  Gold  elsewhere  in  Canada.  Auriferous  gravels 
have  been  located  at  the  headwaters  of  the  Chaudiere  River,  iu 
eastern  Quebec,  and  some  quartz  veins  are  found  in  the  nieta- 
raorphic  rocks  of  the  same  region.     They  have  been  worked  to 


Hep.  U.  S.  Geol.  Survey,  III.,  330.  J.  S.  Campbell,  "Report  on  tlie  Gold 
Fields,  Eastern  Section,"  Halifax,  lSi63;  "Rejmrt  on  the  fiold  Fields." 
Halifax,  1863.  J.  W.  Dawson,  "On  Recent  Discoveries  of  Gold  in  Nova 
Scotia,"  Can.  Nat.  and  Oeol.,  VI.,  417,  1861.  The  various  editions  of 
"  Acadian  Geology,"  of  which  the  third,  London,  is  the  latest,  18T8.  E. 
R.  Faribault,  "Report  on  the  Lower  Cambrian  Rocks  of  (luysljorou^ii 
and  Halifax  Counties,"  Geol.  Snn'ey  Canada,  1H8G,  Rei^rt  P,  l'2!l.  il, 
Fletcher,  "Report  on  Vai-'ous  Counties  in  Nova  Scotia."  Idem,  188(5,  Reitoit 
P.  1-129.  E.  Gilpin,  "The  (^old  Fields  of  Nova  Scotia,"  E)ig.  and  Miii. 
Join'.,  XXXIV.,  a,  IT,  1883.  "  Results  of  Past  Experience  in  Gold  :\Iiiiiii.; 
in  Nova  Scotia,"  Brit.  As.soe.  Adv.  Sci.,  LIII.,  711,  1885.  "Nova  Sc<itiii 
Gold  Mines,"  Traii.'^.  Anier.  In.st.  Min.  Eng.,  XIV.,  674,  1886.  Keo. 
"Notes  on  Nova  Scotia  Gold  Fields,'  Tran.s.  Roy.  Soe.  Can.,  VII..  (i:!. 
1888.  "The  Evidence  of  a  Nova  Scotia  Carboniferous  Conglomerate," 
Idem,  VIIL,  117,  185)0.  "Ores  of  N()\a  Scotia,"  Halifax,  18!)8.  W. 
Gossip,  "The  Rocks  in  the  Vicinity  of  Halifax,  '  Proe.  and  Tran.'i.  Voco 
Scntian  Inst.  Nat.  SeL,  I.,  Part  II.,  44,  18(i4.  "On  tiie  Barrel  Quartz  of 
^Yi\yer\y,"  Idem,  I.,  Part  HI.,  141,  18(i.l.  P.  S.  Hamilton,  "Auriferous 
Deposits  of  Nova  Scotia,"  Idem,  I.,  Part  IV.,  43,  18(i().  C.  F.  Hartt,  "Pre 
Carboniferous  Gold,"  Can..  Nat.,  New  Series,  I.,  4."){),  18t)4.  A.  Ileatbin;,' 
ton,  "Guide  to  the  Gold  Fields  of  Nova  Scotia,"  1868.  H.  Y.  Hind. 
•  Report  on  the  Waverly  Gold  District,"  Halifax,  1S69.  "Gold  Deposits  of 
Nova  Scotia,"  Can.  Nat.,  New  Series,  IV.,  339,  1869.  "Notes  on  tlie 
Structure  of  the  Nova  Scotia  Gold  Districts,  "Proe.  and  Trans.  NovaSeollnii 
Inst.  Nat.  Sci..  II.,  Part  HI.,  103.  "Preliminary  Report  on  a  Gneissoid 
Series  Underlying  the  Gold-bearing  Rocks,"  etc. ,  Halifax,  1870.  See  alsd 
(Jinar.  Jour.  Geol  Soe.,  XXVI.,  468,  1870,  and  Amer.  Jour.  Sci.,  XL, 
347,  1870,  "Report  on  the  Sherbrook  Gold  District,"  etc.,  Halifax.  ISTO. 
"Report  on  the  Mount  Uniacke,  Oldham,  and  Renfrew  Gold  Mining  I 'is 
tNcts,"  Halifax,  1S73.  D.  Iloneyman,  "On  the  (ieology  of  the  (Sold  Fields 
of  Nova  Scotia."  Qnar.  Jour.  Geol.  Soe.,  XVIII.,  342,  1862.  "(^eolog.\  of 
the  (Jay's  River  Gold  Field. "  Prac.  and  Trans.  iXov((  Seotian  Fn.^t.  N<it.  Si-i.. 
H..  76,  1870.  H.  How,  "Mineralogy  of  Nova  Scotia,  "  18(;s,  and  again  in 
official  re|K)rt,  Halifax,  1869.  J.Howe.  "Report  on  the  (told  Fields. 
Halifax.  I860.  "Tangier  Mines,"  report  to  the  Provincial  Secretary,  Hali- 
fax. 1860.  "  Nova  Scotia  Gold  Fields,"  Halifax,  1861.  •■  ReiK)rt  on  (iold 
Fields."  1871.  T.  S.  Hunt,  "Report  on  the  Gold  Regions  of  Nova  Scotia," 
Geol.  Surrey  Can..  1H(i8;  Can.  Nat.,  February,  1868.  W.  E.  Logan,  (-■"/ 
Surrey  of  Can.,  18('»3,  and  atlas,  18().5.  "Notes  on  the  Gold  of  Easiciii 
Canada,'  Montreal,  1864.  J.  Marcou  and  C.  T.  Jackson,  "  Note  on  < 'oM 
Slates  of  Nova  Scotia."  Proe.  Ih^t.  Soe.  Nat.  Hist.,  IX.,  47,  1863.  C  < 
Marsh,  "Ihetiold  of  Nova  Scotia,"  Amer.  Jour.  Sei.,  XXXII.,  395,  ImU. 


GOLD  IN  UNITED  STATES  AND  CANADA. 


401 


;i  small  extent/  Auriferous  niispickel  has  been  developed  in 
considerable  quantity  at  Marmora  (or  Deloro),  Hastings 
I  \)unt5',  Ontario.  It  occurs  with  quartz  in  a  vein  of  complex 
^'eological  relations,  and  after  proving  refractory  to  older 
methods  of  treatment,  has  yielded  to  the  cyanide  process.^ 
Regarding  tlie  mineral  resources  of  tbe  Hudson  Bay  terri- 
tfiry,  some  further  notes  have  been  recorded  by  Dr,  Robert 
Hell.' 

2.1;}.  2  4.  The  following  table  gives  an  idea  of  the  relative 
importance  of  the  several  States.  Full  details  of  the  United 
Spates  and  other  countries  are  given  in  the  Annual  Reports  of 
the  Director  of  the  Mint,  the  21  uieral  Resources  of  the  United 
States  Geological  Survey,  and  the  Mineral  hidusfri/,  the 
annual  statistical  number  of  the  Engineering  and  Mining 
Journal. 

X.  Michel  and  T.  S.  Hunt,  "Report  on  the  Gold  Region  of  Canada," 
Can.  Geol.  Survey,  1860,  49-90.  G.  F.  Monckton,  "  Tlie  Auriferous  Series 
u(  Nova  Sfotia,"  Proc.  Genl.  A.'iHoc,  XL,  45-1,  1891,  London.     H.  F.  Perley, 

Gold  in  Nova  Scotia,"  Cau.  Nat..  IL,  198,  18G5.  H.  Poole,  "Report  on 
( ;()ld  Fields,  Western  Sec-tion,"  Ha'-fax.  186i.  "The  Gold  Leads  of  Nova 
•Si-otia,"  Quar.  Jour.  Geol  Soc,  XXXVI.,  307,  1880.  W.  H.  Prest,  "Deep 
Alining  in  Nova  Scotia,"  Proc.  and  Traim.  Nova  Scotia n  lust.  Nat.  Sci., 
VIIL,  420,  189").  A.  R.  C.  Sehvyn,  "Gold  Fields  of  Quebec  and  Nova 
Scotia,"  fan.  Geol.  Survey,  1870-71,  pp.  2.52-289.  B.  Silliman,  Jr.,  "On 
tlie  so-called  Barrel  Quartz  of  Nova  Scotia,"  Amer.  Jour.  Sci.,  XXXVIIL, 
104,  1864.  "Report  on  the  Lake  Loon  (Jold  Mining  Co.,"  1864.  "Reiwrt 
(111  the  New  York  and  Nova  Scotia  Gold  Mining  Co.,"  1864.  B.  Symons, 
•  The  (iold  Fields  of  Nova  Scotia,"  Trans.  Min.  Aii.-ioc.  and  Lint.  Cornwall, 
III.,  80,  1892.  J.  E.  Woodman,  "Studies  in  the  Gold-bearing  Slates  of 
Nova  Scotia,"  Proc.  Bo.'it.  Soc.  of  Nat.  Hist.  XXVIIL,  ;57r),  1899.  Rec. 
There  are  also  several  official  reports  to  provincial  officers  of  Nova 
Siotia's  l)e|>artment  of  INIines. 

'  R.  W.  Ellis,  •  IJeport  on  the  Mineral  Resources  of  Quebec,"  Geol.  Sur- 
rrji  of  Can.,  New  Series,  1888-89,  Reix>rt  K.  Trails.  Amer.  Inst.  Min, 
/■//(/.,  XVIII.  :116.  A.  Michel  and  T.  S.  Hunt,  "Report  on  the  Gold  Re- 
gions of  Canada,"  Geol.  Surrey  of  Can.,  186»),  49-90. 

'  "The  Marmora  Gold  Mine,"  Eng.  and  Min.  Jour.,  October  33,  1880,  p. 
2(>6.  T.  S.  Hunt,  "  Report  on  the  (iold  Region  of  Hastings.  '  Geol.  Survey 
of  Can.,  Montreal,  1867.  R.  P.  Rothwell,  "The  Gold  i)e{u-ing  Mis|)ickel 
^"ein  of  Marmora,  Ontjirio,"  Tran.H.  Amer.  hist.  Min.  Eng.,  IX.,  p. 
-mil. 

'  R.  Bell,  "Mineral  Resources  of  the  Hudson  Bay  Territories,"  Trans. 
Amer.  Inst.  Min.  Eng.,  XIV.,  690,  1886.  See  also  Trans.  Roy.  Soc.  Can  , 
11.,  341,1885. 


m    ^.A 


402 


KEMP'S  OIIK  DEl'OSITa. 


Alaska  

Arizona 

California 

Colorado 

Georgia 

Idaho 

MichiRan 

Jlontana  

Nevada  

New  Mexico  . . 
North  Carolina 

Oregon 

South  Carolina 
South  Dakota. . 

Texas 

Utah 

Washingtou . . . 
Others 

Total 

Canada 


1890. 


Silver. 


1, 

1, 

24, 

4, 

30, 
5, 
1, 


10, 


S!),6i»7 

1(58,6:5(> 

5307,070 

517 

783.«!{8 

71,111 

36:5,630 

753,535 

680,808 

7,757 

96,969 

517 

129,293 

387,878 

343,434 

90,505 

2,585 


70,485,714 
518.000 


Cold. 


8762,500 

1,000,000 

13,500,000 

4,150,000 

100,000 

1,850,000 

90  000 

3,300,000 

3,800,000 

850.000 

118,500 

1,100,000 

100,000 

3,200.000 

"680,066 

204,000 

40,000 


32,845,000 
1,149,776 


1898. 


Silver. 


8147,500 

1,622,500 

442,500 

13,866,.535 

3,707,999 

'8,'743jui 
826,000 
383,500 

""75,712 

"354, 666 

354,000 

3,876,451 

206,500 

64,037 


34,670,245 
3,616,110 


Gold. 


§3,820,  ()()(( 

2.80(>.(M)(t 

14,9(I0,0(HI 

23,534,.-.;Jl 

3,050,(1110 

"5,247,  (>i  3 

3,0()0,IH)0 

480,000 

"i,3'l'6',(]6!J 

"5,726, 666 

"3.372' 442 
60i),0()0 
340,  s;5 


65,082.4:iil 
13.790  (100 


The  above  figures  for  1 800  are  from  the  Report  of  the  Director 
of  the  Mint  for  that  year.  The  figures  for  1898  are  from  the 
Mineral  Industry,  YIL,  1890.  The  totals  illustrate  the  great 
falling  off  in  the  value  of  silver,  although  the  number  of  ounces 
was  actually  greater  in  1898  than  in  1800.  The  immense  in- 
crease in  the  output  of  gold  is  also  brought  out. 


n 

-   a 

ill 

1 

: 

H 

1 

^IBI 

^H 

i 

H 

H 

I 

WM 

■ 

i 

\ 

H 

1 

fc^ 

H 

1 

8. 


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82,830,0(10 

3.800.0011 

14,900,0(10 

23,534,531 

3,'or)'o',(KM) 

"5,34V.in3 

3,000.00(t 

480,000 

'i,31(K()(W 

'r),T30',(|ii() 


3.373.443 

fioo.ooo 

340,8;  5 

fi5,()83.t:i0 
13,7'.I0  (too 

e  Director 
e  from  the 
the  great 
of  ounces 
Qmense  in- 


CHAPTER  XIV. 

THE  LESSER  METALS:     ALUMINUM,     ANTIMONY,    ARSENIC, 
BISMUTH,   CHROMIUM,    MANGANESE. 

ALUMINUM. 

2. 14.01.  The  importance  of  alumiunm  grows  with  improved 
and  cheaper  methods  of  productiou.  Its  sources  are,  or  have 
been,  alums,  either  natural  or  artificial,  corundum,  cryolite, 
kaolin  and  bauxite.  The  first  of  these  is  formed  in  nature  by 
tiie  decay  of  pyrite  in  shales  and  slates,  and  is  little  if  at  all 
used  as  an  ore  at  present.  The  second  is  more  valuable  as  an 
abrasive,  and  with  the  fall  in  the  price  of  the  metal  has  given 
way  to  other  and  cheaper  ores.  Still  corundum  (AlaO;,)  with 
W.\M  Al,  is  the  richest  natural  mineral.  Crjolite  and  bauxite 
are  now  the  staple  ores,  but  in  the  Grabau  process  kaolin  is 
employed,  although  not  as  yet  in  any  such  amount  as  these 
other  two.  The  fused  cryolite  plaj'sthe  role  of  a  bath  in  which 
the  alumina  is  dissolved  and  reduced  by  electrolysis,  so  that 
really  bauxite  has  come  to  be  the  principal  source.  Cryolite 
occurs  as  an  immense  bedded  deposit  in  gneiss  at  Evigtok,  on 
tlie  Arksut  Fjord,  Greenland.  It  is  mined  as  an  open  cut,  and 
being  noar  the  water's  edge,  on  a  steep  cliff,  after  hand-pick- 
ing, it  is  loaded  directly  upon  vessels,  which  moor  to  the  cliff. 
The  cryolite  is  associated  with  various  related  minerals,  all 
rare  and  mostly  limited  to  this  locality,  with  sulphides  of  iron, 
copper  and  lead,  and  with  siderite.  The  Pennsylvania  Salt 
Co.  of  Natrona,  Pa.,  receives  by  contract  two-thirds  of  the 
output,  the  remaining  third  going  to  Denmark.  The  other 
localties  of  this  mineral,  at  Miask,  in  the  Urals,  and  near  Pike's 
Peak,  Colo,,  are  small  and  commercially  unimportant  pockets. 


m 


! 


1 


404 


KEMPS  ORE  DEPOSITS. 


Cryolite  when  pure  contains  J 3. 02  Al,  and  of  itself  is  thus  fi 
very  low  grade  ore/ 

2.14.02.  Bauxite  (Al-jOa,  3H2O)  is  now  the  main  source  of 
the  metal.  In  the  pure  condition  and  of  the  composition  given 
above  it  contains  Al^O;),  (io.55,  or  Al,  34.94,  but  various  im- 
purities are  always  with  it,  of  which  the  commonest  are  silica. 
oxide  of  iron,  oxide  of  manganese,  carbonates  of  lime  and 
magnesia,  phosphoric  acid,  and,  in  the  Southern  States,  small 
but  constant  amounts  of  titanic  acid.  The  merchantable  ore 
ranges  from  about  40  to  over  60%,  or  even  over  70% 
AlaO;„  but  any  analysis  over  65.55%  AI2O:)  indicates 
a  mineral  of  different  composition  from  AlaO;,,  '4B.X). 
There  is  no  doubt  that  such  exist,  and  in  an  interesting 
paper  entitled  "The  Bauxites :  A  Study  of  a  New  Mineralogical 
Family,"  M.  Francis  Laurhas  advocated  that  there  is  a  whole 
series  of  hydrated  compounds  of  alumina  which  Sre  as 
complex,  perhaps,  as  the  anhydrous  compounds  of  this  metal. 
Bauxite  is  now  known  to  occur  in  economic  quantities  in 
Georgia  and  Alabama,  and  in  Arkansas.  It  has  been  men- 
tioned, however,  from  numerous  other  points  in  States  immedi- 
ately north  of  the  two  former.  The  deposits  in  Georgia  aud 
Alabama''  occur  along  a  narrow  belt  in  the  Coosa  Valley,  ex- 
tending some  sixty   miles  from    Adairsville,    Ga.,    to    Jack- 

'  Ou  the  geology  of  Greeulaml  Cryolite  st'p  Gr.  Hagermann,  "OnM)iiie 
Minerals  associated  with  the  (^ryolite  in  Greenland,"  Amer.  Jour.  Sci, 
ii.,  XLII.,  93.  C.  Hart,  "On  the  Cryolite  Deposit,"  Jonr.  of  Analijt.  and 
Applied  Chem. ,  October.  1892.  G.  Lunge,  in  tlie  treatise  entitled,  "The 
Manufacture  of  Suli)huric  Acid  and  Alkali."  J.  W.  Taylor,  "Cryolite  of 
Evigtok,"  Qnar.  .lour.  Gcol.  Soc,  XII,,  140.  See  also  The  Mineral  /ikIiix 
try,  Vols.  I.  and  II. ,  and  a  pamphlet  iniblished  by  the  Pennsylvania  Salt 
Manufacturing  Co. 

"  Tram.  Amer.  lust.  Mia.  Eng.,  XXIV.,  234,  1894. 

■  C.  W.  Hayes,  "Geological  Relations  of  the  Southern  Appalitcliiiiu 
Bauxite  Deposits,"  Trons.  Amer.  Inst.  Mix.  Eng.,  XXIV.,  348;  also  ^h 
801,  1894.  Rec.  XVI.  Aun.  Rep.  Dir.  U.  S.  Geol.  Survei/,  1894,  III.,  547. 
Rec.     H.  McCalley,  "Alabama  Bauxite,"  Proc.  Alo.  I)i(tti,'it.  and  Sci.  Soc, 

1893.  Reprinted  in  (Seie/tce,  November  25,  1893,  p.  30;!;  ;i  later  p  ler  in  tlie 
issue  January  19,  1894,  p.  29.     "  Bauxite,"  in  The  Mineral  Indudnj,  II  ,  oT, 

1894.  7*m,  v.,  r.l.  Rec.  "Coosa  Valley  Region,"  .4 /a.  Geol.  Snrri'ij, 
1897.  Many  details  as  i>er  index.  E.  Nichols.  "An  Aluminum  Ore: 
Bauxite,"  Trans.  Amer.  Inst.  Min.  Eng.,  XVI.,  90.").  R.  L.  Pack;inl, 
"Aluminum,"  Mineral  Resources,  189i,  147.  J.  W.  Sixjncer,  "Geolngy 
and  Resources  of  Ten  Counties  in  northwestern  ^Georgia, "  p.  310, 1893.    Kec. 


TUE  LEHtiliR  METALS. 


40,) 


II- 


gonville,  Ala.  The  mineral  itself  is  pisolitic  or  oolitic 
in  structure,  as  a  general  thing,  and  the  individual 
masses  are  often  in  concentric  layers,  and  are  held  together 
either  b}'  non-oolitic  bauxite  or  by  silica.  Less  often  the  ore  is 
more  massive,  and  may  be  in  fairly  hard  lumps  or  soft  and 
eurthy.  The  surface  ore  is  often  pitted  and  cellular.  The 
general  geological  relations  will  be  best  understood  by  referring 
to  Fig.  4,  p.  "I'l.  The  region  is  largely  formed  by  Cambrian 
strata,  of  which  the  Connasauga  shales  are  the  upper  member, 
Hiid  the  Rome  sandstone,  or  Weissner  quartzite,  is  the  lower. 
Above  the  Cambrian  is  found  the  Lower  Silurian,  Knox  dolo- 
mite, rich  in  chert.  These  strata  are  broken  by  folds  and  faults 
of  several  series  and  formed  at  different  periods.  The  great 
overthrust  shown  in  Fig.  4  is  of  post-Carboniferous  time,  long. 


Fig.  3 


.       "      BAUXITE-  •    •    ■ 

o       0  GOOQ  ORE'  • 
ORE     X,".   °.     «  •  •  o,  «  .,•    • 
DEPTH  NOT\»     .       ^.   -7>   ^   .  ■  •      . 

KNOWN"^- ^     o  BOTTOM 


V   '     'DBAINAr.EniTRH ^, 


tAV 


Fig.  154. — Cros/isectwn  of  a  Bauxite  depodt  in  Georgia.     After  C.  Willard 
Hayes,  Tram.  Amer.  Inst.  Min.  Ent.,  February,  1894. 


after  the  prin'iipal  Appalachian  upheaval.  C.  W.  Hayes  has 
shown  that  tne  ore  bodies  lie  along  certain  of  these  fault  lines, 
and  the  association  gives  us  a  possible  clue  to  their  method  of 
deposition.  They  are  very  sharply  limited  to  points  lying  be- 
t^\een  the  000  and  960  feet  contours,  and  seem  to  have  been 
u(  i-asioned  by  the  attitude  of  the  land  toward  the  sea  during 
till'  formation  of  the  Tertiary  peneplain  in  the  region. 

rhe  ores  are  always  found  in  the  residual  alteration  products 
of  the  Knox  dolomite,  from  Avhich,  however,  they  are  quite 
sharply  separable.  The  accompanying  cross-section  shows  the 
relations.  While  more  or  less  irregular  in  shape  they  have 
proved  quite  persistent,  and  many  years'  supply  is  now  iii 
si  rht.  Mr.  Hayes  suggests  that  the  crushing  attendant  on  the 
failting,  developed  great  heat,  and   that   atmospheric   waters 


:-^ 


406 


KKMP'S  QUE  DEPOSITS. 


'IMil 


penetrating  along  these  zones  became  charged  with  sulphuric 
acid,  derived  from  decomposing  pyrite.  The  acid  would  dis- 
solve alumina  from  the  Conna.sanga  shales,  possibly  forming 
alums,  with  some  alkali.  Calcium  carbonate  would  react  ou 
such  solutions  so  as  to  precipitate  hydrate  of  alumina,  and  thin, 
rising  as  a  flocculent  precipitate  in  springs,  gave  rise  to  the  o(")li- 
tic  and  pisolitic  deposits,  which  were  afterward,  in  the  decay 
of  the  Knox  dolomite,  involved  in  its  residual  products.  The 
explanation  is  reasonable  and  has  great  claims  to  confidence. 
The  same  general  hypothesis  may  be  applied  to  the  neighboring 
limonites.  H.  McCalley  gives  in  Science,  January  21),  1804,  p. 
;j{),  the  following  working  analyses  from  the  War-whoop  Bank, 
The  analyses  are  based  on  samples  from  car-load  lots,  and  rejiie- 
sent.'iOO  to  1,000  tons.  The  first  column  is  the  variety  called 
"Hard  White  Ore";  the  second,  known  as  "War-whoop  Ore," 
is  the  average  of  consumer's  analyses. 

First.  Second. 

Aliunina 57.-63.  56.-63. 

Ferric  oxide luuler  1.  3.5-3.0 

Silica,  about 3.50  5.00 

Titanic  acid 3.0-4.0  3.0-4.0 

Water,  combined 29.0-30.0  about  30.0 

Moisture,  hygroscopic 3.0-4.0  3.0-4.0 

A  little  over  half  (53.3%)  of  the  alumina  is  the  metal  itself. 

2.14.03.  The  bauxite  deposits  of  Arkansas  are  found  witliin 
a  few  miles  of  Little  Rock,  and  further  west  in  Saline  County, 
near  the  town  of  Bryant.  T.bey  favor  the  contact  of  the  intruded 
syenites  (regarded  as  Cretaceous)  and  Paleozoic  sediments,  Imt 
they  are  themselves  involved  in  most  cases  in  Tertiary  sand- 
stones. The  association  with  syenite  is  quite  invariable.  The 
bauxite  is  pisolitic  and  concretionary.  The  range  in  composition 
is  consideralile,  some  being  high  in  iron,  others  in  silica,  while 
others  are  fairly  pure.  The  variability  even  in  the  same  open- 
ing is  considerable,  as  indeed  is  always  the  case  with  depoisits 
of  this  character.  The  deposits  are  individually  somewhat 
irregular  in  shape  and  extent,  but  the  quantity  is  large.  J.  C. 
Branner  regards  them  as  shore  deposits,  probably  formed  after 
the  manner  of  oolitic  concretions,  which  derived  their  hydrjite 
of  alumina  from  the  syenite,  through  the  medium  of  liot 
springs.     A  submergence  of  the  still  heated  syenite  beneath 


MHaMtB 


TUE  LESS  Eli  METALS. 


407 


f^ea  water  is  suggested  as  a  possible  explanation  of  the  solution 
and  deposition.  Dr.  Branner  gives,  in  the  reference  from  the 
Jonrnnl  of  (ieoloyy,  cited  below,  a  comi)lete  bibliography  and 
review  of  the  literature  on  bauxite  and  of  the  views  regarding 
its  origin.^ 

2.14.04.  W.  P.  Blake  has  described  deposits  of  alunogen  and 
liauxite,  on  the  upper  Gila  River,  about  40  miles  north  of  Sil- 
ver City,  New  Mexico.  The  bauxite  has  resulted  from  the 
action  of  sulphuric  acid,  produced  in  the  decay  of  pyrites,  upon 
basalts.  Alunogen  and  sulphate  of  iron  are  removed  while 
bauxite  remains  as  a  residual  deposit.  The  geological  relations 
are  therefore  ver}'  like  those  of  Glenariff,  County  Antrim, 
Ireland,  and  of  the  Vogelsberg,  Germany.'"'  The  Gila  River 
deposits  are  too  remote  for  utilization  imder  present  conditions. 

Bauxite  is  employed  for  many  other  purposes  besides  fur- 
nishing an  ore  of  aluminum,  as  this  is  one  of  its  later  adapta- 
tions. Great  quantities  are  used  to  produce  alums,  and  as  a 
refractory  material  it  has  long  been  appreciated. 

•■2.14.0').  In  the  earlier  development  of  the  aluminum  indus- 
try corundum  was  somewhat  sought  as  an  ore.  The  varieties 
with  vitreous  luster  and  light  colors  are  called  sapphire,  the 
duller  and  more  smoky  ones,  corundum,  while  the  impure 
ivinds,  which  are  mixed  more  or  less  with  magnetite,  hematite, 
spinel,  etc.,  pass  under  the  name  of  emer}'.  The  last  named  is 
I  if  no  importance  in  this  connection.  Some  sapphire  and 
corundum  have  been  obtained  in  Chester  County,  Penn.,  but 
jnactically  the  only  source  of  any  moment  in  the  United  States 
is  in  a  belt  of  a  curious  rock  called  dunite,  which  consists  of 
S,nains  of  olivine,  and  which  traverses  western  North  Carolina 

'  J.  C.  Branner,  "Bauxite  in  Arkansas,"  Ame)\  Gcol,  VII.,  181,  1891. 
All  extended  rejxjrt  was  announced  for  Vol.  I.,  1889,  of  Dr.  Branner's 
Aiiuual  Reports  as  State  Geologist  of  Arkansas,  but  it  has  not  yet  (1899) 
lieen  issued.  Preliminary  reports  appear  in  the  ArkniisaN  Gazettt^  and 
■  \ih-a)imsD(')iiocrnt,  little  Rock,  January  8,  1891.  Third  Biennial  Report, 
I'meau  of  Jlines,  Manufactures  and  Agriculture  of  the  State  of  Arkansas, 
loi- 1893  and  1894,  Little  Rock,  1894,  119-125.  Fourth  Biennial  Report,  Little 
Uofk.  189(5.  10r)-lin.  '•  The  Bauxite  Deposits  of  Arkansas,"  Jo»>-.  of  Gcol, 
\  .  2(>3, 1897.  J.  Francis  Williams,  Aim.  Rep.  Ueol.  Survey  Ark.,  1880,  II., 
104. 

■  W.  P.  Blake,  "Alunogen  and  Bauxite  of  New  Mexico,"  Trans.  Amer. 
//.sY.  Mill.  Eiig.,  XXIV.,  571. 


ill 


I'  'I 


m 


III 


;S  •; 


iilli 


t08 


KEMP'S  ORE  DEPOSITS. 


and  Georgia.  The  corundum  occurs  along  the  contacts  of  tlni 
dunite  and  a  hornblende  gneiss  with  which  it  is  associattd. 
It  lies  in  scattered  lumps  distributed  through  (lecomposfd 
micaceous  material,  which  is  at  times  so  soft  as  to  be  vashcil 
out  in  the  hydraulic  way.  In  some  instances  the  mineral  hji- 
pears  to  have  resulted  from  some  reactionar}-  etfects  of  the  t^\() 
rocks,  or  of  solutions  emanating  from  them,  on  each  otlui . 
The  gneiss  is  aluminous,  the  dunite  magnesian/  Again  it 
seems  to  have  crystallized  directly  from  fusion  and  to  have 
become  concentrated  near  the  walls,  either  from  the  operation 
of  Soret's  law,  or  from  convection  currents  as  described  under 
1.0(1.1:5.'^  J.  H.  Pratt  has  even  been  able  to  apply  the  re><ii Its 
experimentally  obtained  by  J.  Morozewicz  to  the  rocks  which 
yield  the  corundum,  and  has  made  the  following  summary  ;is 
the  result  of  his  observations  and  analyses,  dealing  in  all  caj^ts 
with  peridotites. 

1.  When  the  magma  is  a  calcium-sodium-potassium  silicate, 
no  alumina  held  in  solution  will  separate  out  as  corundum,  ex- 
cept when  the  ratio  of  the  alumina  to  the  other  bases  is  nioie 
than  1 : 1,  and  the  ratio  of  the  silica  is  less  than  0.     (Molecular 


■  T.  M.  Chatard,  Mineral  ResonrccH,  U.   S.   Gcol.   Survey,  1883-S4.  714. 
Rec.     "Tlie  Gneiss  Dunite  Contacts  of  Corundiiin  Hill,  N.  C,"  etc..  Bull. 
U.  S.  Gcol.  Siirvei/,  XLII.,  4'),  1881.     Rec.     Short  ub.stract  iu  the  Eikj.  nml 
Min.  Jour.,  July  21,  1888,  p.  46.     J.  P.  Cooke.  Proc.  Amer.  Acad..  IX,,  4M, 
1874.     F.  A.  Centli,    "Corundutn:  Its   Alterations   and    Associated   Miii 
erals,"  Avicr.  Phil.  Soc,  8eptend)er  19,  1878;  July  17,  1874;  Aincr.  Janr. 
Sci.,  iii.,  VI.,  401,  1873.     T.  8.  Hunt,  TrmiH.  Ron.  Soc.  Can.,  II.,  1884.      ' 
W,  Jenks,  Quar.  Jour.   Gcol.  Soc.,  XXX.,  !}03,  1874.     A.  A.  Julien,  I'n- 
Boat.  Soc.  Nat.  Hint..  XXII.,  131,  1893.     W.  C   Kerr,    "CeoloRy  of  Xoiili 
Carolina,    Supplement,"  (14,    1875.     F.  P.  King,  "Preliminary   Kepoit  in 
Corundum  DeiKisits  of  Georgia,"  Geol.  Snin'cy   Georgia.  Bulletin  2,  18!M. 
J.V.Lewis,  "Corundiun   in  the   Appalachian    Crystalline   Belt,"  r/vn/.v. 
Amer.  hist.  Min.  Eiiij..  XXV.,  832,  1S9r).     Rec.     R.  W.  Rayi'i<"id,  "Jeiik-s' 
Corundum  Mine,  N.  C,"   Trans.  Amer.    Inat.  Min.  Enrj.,  VII.,    83,   1878. 
C.  U.  Sheimrd,  "On  tlie  Corundum  Region  of  North  Carolina  and  Geor- 
gia," Auier.  Jour.  Sci.,  iii.,  IV.,  109,  17.1,  1872.     Rec.     C.  D.  Smith,  "Geil 
ogy  North  Carolina,  I.,  Appendix  D.,"  91,  1875;  II.,  43,  1881.     J.  L.  Smitli 
"Notes  on  the  Corundum  of  North  Carolina,  Georgia,"  etc.,  Amer.  Jour. 
Sci,  iii.,  VI.,  180,  1873.    Rec.    M.  E.  Wadsworth,  Mem.  Mus.  Comjx  ZonL. 
XI.,  Parti.,  p.  118,  1884. 

'J.H.Pratt,  "On  the   Origin  of  the  Corundum   A.ssociated   with  \hc 
Peridolites  in  North  Carolina,"  ^nipr.  Jour.  Sci.,  July,  1898,  p.  49. 


iK: 


THE  LESSER  METALS. 


409 


iBelt,"  T/vMis. 


Ina  and  Geoi 


Ited    with  tlie 


ratios  are  nieHnt,  i.e.,  the  quotients  obtained  bj' dividing  the 
percentuf^e  by  the  molecular  weight  in  each  case.) 

'Z.  If  magnesia  and  iron  are  present  in  the  above  magma, 
corundum  will  not  form  unless  there  is  more  than  enough 
alumina  to  unite  with  the  magnesia  and  iron  (that  is,  spinels 
will  form  in  preference  to  corundum  where  possible). 

,3.  When  the  magma  is  composed  of  a  magnesium  silicate 
without  excess  of  magnesia,  all  the  alumina  helu  by  such  a 
magma  will  separate  out  as  corundum. 

4.  Where  thare  is  an  excess  of  magnesia  in  the  magma  just 
described,  this  will  unite  with  a  portion  of  the  alumina  to  form 
spinel,  and  the  rest  of  the  alumina  will  separate  out  as  corun- 
dum. 

5.  Where  there  is  chromic  oxide  in  a  magma  composed  es- 
sentially of  a  magnesium  silicate  (as  the  peridotHe  rocks),  and 
only  a  very  little  alumina  and  magnesia  are  jireseut,  these, 
uniting,  separate  out  with  chromic  oxide  to  form  the  mineral 
chromite,  and  no  corundum  or  spinel  is  formed. 

(i.  When  peridotite  magmas  contain,  besides  the  alumina, 
oxides  of  the  alkalies  and  alkali-earths,  as  soda,  potash  and 
lime,  a  portion  of  the  alumma  is  used  in  uniting  with  these 
(ixides  and  silica  to  form  feldspar. 

7,  There  is  a  strong  tendency  for  the  alumina  to  unite  with  the 
alkali  and  alkali-earth  oxides,  to  produce  double  silicates  like 
feldspars,  whether  such  silicates  form  the  chief  minerals  of  the 
resulting  rock,  or  are  present  only  in  relatively  small  amount. 
There  is,  however,  but  little  tendencj'  for  the  alumina  to  unite 
with  magnesia,  to  form  double  silicates,  when  the  magma  is  a 
magnesium  silicate.' 

2.14.06.  The  most  important  recent  discovery  of  corundum 
ill  commercial  quantities  is  that  of  the  deposits  associated  with 
the  belt  of  nej.heline  syenite  that  covers  a  large  area  in  eastern 
Ontario,  north  of  Kingston.  The  syenite,  which  is  at  times 
viry  coarsely  crystalline  and  pegmatitic,  contains  crystals  of 
ciirundum,  often  of  large  size  and  of  considerable  regularity  of 
form.  Blue  sodalite  also  occurs  in  tlie  rock  in  large  masses. 
Fxperiments  in  concentration  have  been  carried  on  at  the 
S  hool  of  Mines  in  Kingston  under  Professor  Miller,  and  actual 

J.  H.  Pratt,    "On   the  Separation  of  Ahiniina  from  Molten  Magmas, 
and  the  Formation  of  Corundum,"  Amcr.  Joiw.  Sei.,  September,  1892,  227. 


v 


410 


KEMP'S  OltK  DEPOSITS. 


development  is  probable  at  an  early  date.'  Corundum  of  jjotn 
grade  baa  been  mined  at  Yogo  Gulch,  Mont.,  and  beautilul 
sapphires  are  obtained."  The  commercial  emery  employed  in 
America  is  largely  imported  from  Smyrna,  but  it  has  no  bear- 
ing on  the  production  of  aluminum.  It  is  also  mined  at  Che.S' 
ter,  Mass.,  and  near  Peokskill,  N.  Y.-"  Corundum  is  reportou 
in  vast  amount  in  India.* 

ANTIMONY. 

Senarmontite,  SboOs;  Sb.  K\M>\  O.  10.44, 

Stibuite  (Antimonite,  Antimony  Glance),  SbjSs;  Sb.  71.8; 
S,  28.'^. 

2.14.07.  Antimony  occurs  in  composition  with  several  silver 
ores,  but  almost  its  sole  commercial  source  is  stibnite.  Tlie 
oxide,  senarmontite,  is  rarely  abundant  enough  to  be  an  ore. 
Stibnite  was  one  of  the  minerals  formerly  cited  as  having' 
originated  in  veins  by  volatilization  from  lower  sources.  But 
it  lias  probably,  in  all  cases,  been  derived  from  solutions  of 
alkaline  sulphides. 

'Z.  14.08.  Example  47.  Veins  containing  stibnite,  usually  in 
quartz  gangue.  California,  Kern  County.  At  San  Emigdio 
a  vein  of  workable  size  has  been  found.  It  has  a  quartz  gangiie 
and  is  in  granite.  The  vein  varies  from  a  few  inches  to  several 
feet  across,  and  has  afforded  some  metal.  Several  others  are 
known  in  San  Benito  and  Inyo  counties. 

*  F.  D.  Adams,  "Report  on  the  Geology  of  a  Portion  of  Central  Ontario," 
Oeol.  Survey  Can.,  1893-3,  Report  .T,  5.  "  Occurrence  of  a  Large  Area  of 
Nepheline  Syenite  in  the  Township  of  Dungannon,  Ontario,"  Amer.  Jour. 
Sci.,  .T.ily,  1804,  10.  (The  coriinduni  had  not  been  discovered  when  tlu'se 
two  papers  were  issued.)  Archibald  Blue,  "Coruntluni  in  Ontario," 
sillier.  Iiisf.  Mill.  Eng.,  Buffalo  meeting,  ISiKS.  A.  P.  Coleman,  "Coniii- 
diferous  NepiielineSyenite  from  Eastern  Ontario,"  Jour.  Oral.,  Vll  , 
.July-August,  1899,  437.  B.  J.  Harrington,  "Neplieline,  Sodalite  ami 
Oithoclase  from  the  Nepheline  Syenite  of  Dungannon,  Ont.,"  Auicr.  Joiw. 
Sci.,  July,  1894,  16.  W.  G.  Miller,  "  Report  of  Ontario  Bureau  of  Mines," 
VII.,  207,  1898. 

"  L.  V.  Pirsson,  "Corundum-bearing  Rock  from  Yogo  Gulch,  Mont.," 
Amer.  Jour.  Sci.,  December,  1897,  421. 

'  J,  I).  Dana,  Avwr.  Jour.  Sci.,  September,  1880,  199.  J,  P.  Kimball, 
Amer.  Chemist,  IV.,  1874,  ;}21.  Trans.  Amer.  Inst.  Min.  Eng.,  IX.,  19, 
1881.     G.  H.  Williams,  xhner.  Jour.  ScL,  March,  1887,  197.     Rec. 

*  T.  H.  Holland,  "Corundum  ":  in  "A  Manual  of  the  Geology  of  India," 
Economic  Oeol,  Part  I,,  1898,  l-()9. 


TlIK  LESSA'li  METALS. 


411 


ilch,  Mont ,' 


2.14.00.  Nevada,  Humboldt  County.  Stibnito  has  been 
known  for  sonu)  years  in  veins  with  ijuartz  gangue.  The 
Thies-Hutchtjus  niines,  about  1')  miles  from  Tiovclock  station, 
were  productive  in  isni.  Lander  County.  The  moat  impor- 
tant of  the  American  mines  are  the  Beulah  and  Genesee,  at  Big 
Creek,  near  Austin.  The  vein  is  reixjvted  as  showing  three 
feet  of  nearly  pure  stibnite.  It  protluced  ^(>(»  tons  of  sulphide  in 
is'.n,  and  was  operated  in  lSlt2. 

'i.14.10.  Arkansas,  Sevier  County.  Stibnite  occurs  in  veins 
with  (juartz  ganguo  in  southwestern  Arkansas.  Some  attempts 
have  been  made  to  develop  tliem,  but  the  ore  is  reported  to  be 
too  remote  for  profitable  working.  The  veins  ai)i)ear  to  be  gen- 
erally interbedded  in  Trenton  shales  and  to  lie  along  anticlinal 
axes,  which  trend  northeast.  They  are  all  controlled  by  the 
United  States  Antimony  Company,  of  Philadelphia. 

"2.14.11.  New  Brunswick,  York  County.  Veins  of  (juartz 
or  quartz  and  calcite,  carrying  stibnite,  occur  over  several 
s([uare  miles.  Tlie  wall  rocks  are  clay  slates  and  sandstones  of 
Cambro-Silurian  age.  The  mines  have  been  commercially  pio- 
<luctive.     The  veins  vary  from  a  few  inches  to  six  feet. 

1:3.14.12.  Example  4S.  Utah,  Iron  County.  Disseminations 
of  stibnite  in  sandstone  and  conglomerate,  following  the  strati- 
fication. In  Iron  County,  southwestern  Utah,  masses  of  radiat- 
ing needles  occur  in  sandstones  and  between  the  boulders  of  an 
associated  conglomerate.  Very  large  individual  pieces  have 
been  obtained,  but  not  enough  for  profitable  mining.  Blake 
ihinks  that  the  ore  has  crystallized  from  descending  solutions. 
Eruptive  rocks  are  present  above  the  sandstones. 

3.14.1.'5.  An  interesting  deposit  of  senarmontite  was  worked 
for  a  time  in  Sonora,  just  south  of  the  Arizona  line,  but  it  was 
soon  exhausted.^ 


'  General  References:  W.  P.  Blake.  "General  Distribution  of  Ores  of 
Antimony,"  Min.  Resources  of  the  U.  S.,  1883-84,  p.  641.  Arkansas:  T.  B. 
Coiustocik,  Geol.  Siirvi'n  of  Knu.,  1888,  I.,  p.  136.  F.  P.  Dunnington, 
'  Minerals  of  a  Deposit  of  Antimony  Ores  in  Sevier  County,  Ark.,"  Ainei'. 
-I.s'soc.  Arts  and  ScL,  18T7.  Rec.  J.  W.  Mallet,  Chem.  News,  No.  533.  C. 
1.  Waite,  "Antimony  Deposits  of  Arkansiis,"  Trans.  Amer.  Inst.  Min. 
I'iKj.,  VII.,  42.  C.  P.  Williams,  "Notes  on  tlie  Occurrence  of  Antimony 
in  Arkansas,"  LJem,  III..  mO.  California:  W.  P.  Blake,  "Kern  County," 
U.  S.  Pac.  R.  R.  Explor.  and  Survey,  Vol.  V.,  p.  291.  H.  G.  Hanks,  Rep. 
Cal.  State  Mineralogist,  1H84.      See  also  subsequent  reports  by  William 


H^"l« 


412 


KEMP'S  ORE  DEPOSITS. 


■  lii 
Si! 


ARSENIC. 

2.14.14.  This  metal  occurs  with  nany  silver  ores  in  the 
"West  and  in  arisenopyrite,  or  mispickel,  a  not  uncommon  arseno- 
sulphide  in  the  gold  quartz  veins,  east  and  west.  At  the  Gat- 
ling  mines,  in  the  town  of  Marmora  (more  lately  called  Deloro), 
in  Hastings  County,  Ontario,  auriferous  mispickel  occurs  in 
great  quantity  in  granite,  in  veins  with  quartz  gangue.  Con- 
siderable oxide  of  arsenic  has  been  obtained  in  the  past  from 
the  roasters,  but  in  recent  years  the  cyanide  process  has  been 
employed.  For  reference  to  the  printed  descriptions  se 3  under 
"Gold  in  Canada"  (2.13.07).  Considerable  arsenic  is  also  pro- 
duced as  a  by-product  in  treating  the  ores  of  the  Monte  Cristo 
mines  of  Washington  State. 

BISMUTH. 

2.14.15.  Bismuth  occurs  with  certain  silver  ores  in  the  Sau 
Juan  district,  Colorado,  and  is  referred  to  in  the  description  of 
the  country  under  "Silver  and  Gohl"  (2. ()'.».  10).  Lane's  mine, 
at  Monroe,  Conn.,  has  furnished  museum  specimens  of  native 
bismuth  in  quartz.  Some  neighboring  parts  of  Connecticut 
have  afforded  bismuth  minerals,  and  not  a  few  other  places  in 
the  country  contain  traces,  but  the  San  Juan  is  the  only  serious 
one  as  yet.^ 

CHROMIUM. 

2.14.16.  Chromite,  whose  theoretical  composition  is 
FeO.Cr.O;,,  with  Cr^O^  68%.  often  has  MgO  and  Fe^Os  re- 
placing its  normal  oxides.  The  percentage  of  CraO.-)  is  thus 
reduced.  It  is  alwa>3  found  in  association  with  serpentine, 
which  has  resulted  from  the  alteration  of  basic  rocks  consisting 
of  olivine,  hornblende,   and  pyroxene.     These  minerals,  or  at 

Irelan,  Jr.  Mexico:  E.  T.  Cox,  "Discovery  of  Oxide  of  Antimony  in  So- 
nora,"  Ainer.  Jour.  Sci.,  XX.,  431.  J.  Douglass,  "Tlie  Antimony  Deposit 
of  Sononx,"  Eng.  and  Miu.  Jour.,  May  21,  1881,  p.  ;35G.  Nevada:  Menu 
1892,  p.  (5.  New  Brunswick;  L.  W.Bailey,  "Discovery  of  Stibnite  in 
New  Brunswick,"  Ainer.  Jour.  Sci.,  ii.,  XXXV.,  IfH).  and  in  Rep.  on  ilie 
Geol.  of  New  Brunswick,  ISfi.");  also  H.  Y.  Hind,  in  thj  •same.  Utah:  l>. 
B.  Huntley,  Tenth  d'nsus.  Vol.  XIII.,  p.  46:5. 

'  Min.  Resources  of  the  U.  S.,  1885,  p.  399.     B.  Silliman,  "  Bismuthiuite 
from  the   Granite  District,  Utah,"  A)ner.  Jour.  Sci.,  iii.,  VI.,  128.     H.  L. 
Wells,  "  Bisnuithospliauite  from  Willimautic  and  Poiijland,  Conn.,"  Ann  ' 
Jour.  Sci.,  iii.,  XXXIV.,  271. 


THE  LESSFIB  METALS. 


413 


,  in  tho 
arseno- 
he  Gat- 
Deloro), 
3curs  ill 
.     Con- 
ist  from 
as  been 
:3  under 
also  pro- 
,e  Cristo 


1  the  San 
nptiou  of 
e's  mine, 
Df  native 
nnecticut 
places  in 
,v  serious 


ition     is 

P(v,0:,  re- 
is  thus 
;rpentine. 
■onsistiug 
Is,  or  at 

lony  in  So- 
Iny  Deposit 
ula:  Mi'iii- 
Btibuite  in 
lep.  on  r/V' 
Utah:  l». 

Imnuthiiii'e 
2-6.     H.  '  • 


least  the  pyroxenes,  contain  chromium  as  a  base,  but  in  the 
unaltered  rock  there  is  no  question  that  chromite  itself  has 
formed  one  of  the  component  minerals,  just  as  magnetite  so 
commonly  occurs  in  this  relation.  A  chrome  spinel,  picotite  is 
also  not  unusual.  The  basic  rocks,  peridotitesand  pyroxenites, 
almost  alwaj's  yield  on  analysis  some  chromic  oxide,  and  may 
in  extreme  cases  afford  several  per  cent.  Vogt  gives  in  the 
paper  cited  below  a  serie:*  of  percentages  from  (),'^5  to  3.55  in 
twelve  peridotites,  from  various  localities.  The  invariable 
association  of  the  metal  with  rocks  rich  in  magnesium  is  strik- 
ing. Inasmuch  as  the  chromite  occurs,  when  mined,  in  ser- 
pentine, a  secondary  rock,  it  has  usually  been  believed  that  it 
was  a  product  set  free  in  the  change  from  the  anhydrous 
original  to  the  hydrated  derivative.^  Meuuier  has  referred  it 
to  the  action  of  vapors  or  to  a  pneumatolj^tic  process  in  the 
still  molten  peridotite  magma.  Vogt,  however,  includes  the 
chromium  ore  bodies  in  the  category  of  those  formed  by  direct 
crystallization  from  a  molten  magma,  and  regards  the  chromite 
of  the  serpentines  simply  as  the  original  crystallizations  which 
have  resisted  alteration,  while  their  associated  minerals  nave 
undergone  hydration  and  change.  As  chromite  isamineial 
that  is  extremely  resistant  to  the  action  of  the  natural  solvents 
and  reagents,  this  view  has  much  to  commend  it.  Dynamic 
metamorphism  might  afterward  drag  out  the  masses  of  chro- 
mite into  a  lineal  alignment.  Vogt  also  describes  a  fresh  perid- 
otite from  Hestmando  under  the  pclar  circle  in  the  extreme 
north  of  Norway,"  that  is  aLuost  or  quite  rich  enough  in 
chromite  to  be  worthy  of  exploitation.  Hydrated  nickel  com- 
(lounds  are  often  associated  with  chromite. 

[n  recent  investigations  of  vhe  chromite  deposits  of  North 
Carolina,  J.  H.    Pratt'  has   reached   the  conclusion    that  the 

'  .See  in  this  connection  the  following,  wliicli  are  cited  by  Vogt,  Ccssa 
:,iid  Arzruni,  Zeitsehr  f.  Kryntal.,  VII.,  p.  1.  1888.  A.  v.  Groddeck, 
l.iJwe  i-on  den  Ldger.statteii  der  Erze,  14(5,  1879.  A.  Ilelland,  OcncIIncIi. 
ii'i'  WinHennchaften-Kristiania,  1873.  L.  de  Lauiiay,  Formation  Gitea 
Mi'tidli feres,  18!);l 

■  J.  H.  L.  Vogt,  Zeits.  fiir  prakt.  Geol..  1894.  885.  L.  de  T,aunay  sup- 
li 'its  the  same  view,  A nn ales  des  Mines,  XII.,  1897,  17'). 

^  J.  H.  Pratt,  "On  the  Occurrence,  Origin  and  (liemical  Composition 
<''■'  Chromite,"  Trans.  Amer.  Inst.  Min.  Eng.,  New  York  meeting,  Feb- 
iiiary,  1899.  Abstract  in  Eng.  and  Min.  Jour.,  December  10,  1898.  Re- 
tt is  especially  to  North  Carolina. 


Ml 


414 


KKMF8  ORE  DEPOSITS. 


mineral  has  crystallized  from  fusion,  and  has  become  concen- 
trated near  the  walls  by  convection  currents,  as  described  un- 
der 1.0(;.13. 

2.14.17.  The  chromite  of  commerce  should  contain  at  least 
60/0  CrjOg.  Values  over  this  command  a  premium,  while 
those  below  50  siiffer  severe  rebates.  The  less  silica,  the 
better.  Wm.  Glenn  cites  the  following  three  analyses  as 
typical  of  the  run  of  the  commercial  product,  the  sources  of  the 
ore  not  being  given.  {XVll.  Annual  Report  Director  U.  S. 
GeoL  Soc,  Part  III,  2G3.) 

SiO., 7.00  (5.23  6.44 

Cr,63 39.15  51.03  53.07 

Feb  27. 13  13.06  15.27 

MgO 16.11  1G.33  16.08 

CaO 3.41  3.61  1.20 

AlgOa 7.00  12.16  8.01 

99.79  100.40  100.07 


li!f 


llj 


i»  !£  I' 


Chromite  in  the  arts  is  chiefly  employed  in  the  manufactun^ 
of  potassium  or  sodium  bichromate,  so  essential  to  dyeing,  but 
of  late  years  it  is  also  proving  of  great  value  as  an  ingredient 
of  refractory  bricks,  and  as  a  lining  for  furnaces. 

2.14.18.  Example  40.  Disseminations  of  chromite  in  ser- 
pentine. Pennsylvania  and  JVIaryland.  Great  areas  of  serpen- 
tine are  found  in  southeastern  Pennsylvania  and  in  the  adja- 
cent parts  of  Delaware  and  IMaryland.  Considerable  minini,' 
has  been  done  in  the  past.  Where  first  obtained  the  chromite 
occurred  :'n  loose  masses  in  the  residual  soil  on  the  surface.  Jt 
was  identified  and  gathered  in  Harford  County,  Maryland,  as 
early  as  1827  by  Isaac  Tyson,  Jr.,  and  found  a  ready  marktt 
abroad,  to  such  an  extent  that  from  1827  to  IKliO  the  Baltimore  iv- 
gion  was  the  chief  source  of  the  mineral  for  the  world.  In  the  scr- 
pentiiies  of  neighboring  parts  of  Marj-land  and  in  southeastein 
Pennhylvania  other  deposits  were  found  in  the  years  following 
1827,  and  a  very  important  industry  sprang  up.  The  largest 
proved  to  be  the  Wood  Pit  or  Mine  in  Lancaster  County,  Penn- 
sylvania, and  it  developed  the  most  productive  single  deposit 
yet  known.  It  has  been  worked  to  a  de[)th  of  7(»()  feet  or  moie 
— a  striking  thing  for  chromite,  whose  deposits,  as  a  rule,  are 
very  limited  in  depth  and  extent,  and   very  pockety.     The  sd- 


THE  LESSER  METALS. 


415 


B  conceB 
ribed  un- 

n  at  least 
um,  while 
silica,  the 
aalyaes  as 
irces  of  the 
xtuv  U.  is. 


.44 

.07 
.27 
.08 
.20 
^.01 

0.07 

maimfactnre 
,  dyeing,  hut 
n  ingredient 

>mite  in  ser- 
las  of  aer pen- 
ill   the  adja- 
able  mining' 
the  chroniite 
surface.     H 
Maryland,  as 
eady  nmilit't 
Baltimore  1"- 
(1.   Intheser- 
southeasteiu 
rs  following 
The   largest 
ounty,  Penn- 
iugle  deposit 
feet  or  more 
as  a  rule,  ai'© 
ety.     The  bo- 


called  Texas  mine  near  or  on  the  Maryland-Pennsylvania  line 
also  became  well  known.  In  addition  to  the  surface  boulders 
and  included  masses,  chroniite  sand  of  commercial  grade  has 
been  obtained  from  the  beds  of  streams  in  this  belt,  and,  as 
stated  by  Wm.  Glenn,  the  supply  is  renewed  after  an  interval 
of  about  fifteen  years.  The  work  of  G.  H.  Williams  and  F.  D. 
Chester  has  shown  the  great  abundance  of  basic,  plutonic  rocks, 
gabbros,  pyroxenites,  peridotites  and  the  like  in  this  region, 
and  there  is  every  reason  to  regard  the  serpentines  as  derivatives 
from  such  originals.  During  the  process  of  alteration  what- 
ever chromite  there  was  present  in  the  fresh  igneous  rock, 
was  reinforced  by  the  formation  of  secondary  chromite  from  the 
alteration  of  chromiferous  pyroxene,  and  other  minerals,  but 
only  rarely  were  sufficient  amounts  produced  to  warrant  min- 
ing. Dynamic  metamorphism  may  have  strung  them  out  in 
linear  alignment. 

2. 14. 11).  Chromite  has  also  been  met  in  several  places  in  the 
south,  but  never,  as  yet,  in  minable  amounts.  The  Baltimore 
region  itself  has  not  been  active  for  some  years.^ 

2.14.20.  California.  As  already  mentioned  under  the  pre- 
cious metals,  great  areas  of  serpentine  occur  on  the  western 
thinks  of  the  Sierras  and  in  the  Coast  range.  In  Del  Norte, 
San  Luis  Obispo,  Placer,  and  Shasta  counties,  California,  they 
furnish  commercial  amounts  of  chromite.  In  some  i)laces  the 
ore  is  followed   by  underground  mining,   and  in  others  it   is 


iilr 


'  F.  D.  Cliester,  in  the  Ann.  Rep.  Peiin.  Geol.  Suri'ey,  1887,  describes 
the  Serpentine  alon<;  the  State  line  with  Delaware.  D.  T.  Day,  Miiwral 
licsoiti'ces,  and  since  1804.  Ann.  Rcj)^.  of  the  Dir.  of  U.  S.  Geol.  Snnri/.  1883, 
[>.  428;  especially  188:5-84,  p.  567.  J.  Eyeiinan,  "On  Woods  Mine,  Pa.,"  Miii- 
I  (ilogij  of  Penn.,  Easton,  1880.  P.  Eraser,  "  The  Northern  Serpentine  Belt 
in  Chester  Connty,  Pa.,"  Trans.  Anirr.  Inst.  Min.  Eihj..  XII.,  iJlO.  Report 
<  o,  Lancaster  Co.,  Penn.,  Geol.  Survey.  Rec.  T.  H.  Garrett,  "Chemical 
I'.xaniiuatiou  of  Minerals  Associated  with  Seqientine,"  Anier.  Jour.  Sei., 
ii.,  XIII.,  45,  and  XV.,  im.  F.  A.  Genth,  Idem,  ii.,  XLI.,  120.  Wm. 
(Ueun,  "Chrome  in  the  Southern  Appalachian  Region,"  /'/•(Oi.s.  ^mer. 
lust.  Min.  Eng..  XXV.,  481.  Rec.  J.  II.  Pratt,  "The  Occurrence,  Origin 
.iiid  (^hemical  Composition  of  Chromite,"  7'/y(»,s'.  Anier.  Li.^t.  Mu'  Eng., 
1  il)ruary,  1890,  New  York  meeting.  G.  II.  Williams,  "The  Gabbros  and 
-Associated  Hornblende  Rocks  near  Baltimore,"  Bull.  'J:i,  U.  S.  Geol. 
Siirvei/.  "The  Geology  of  the  Crystalline  Rocks  near  Baltimore,"  dis- 
ti  Inited  at  the  Baltimore  meeting  of  the  Anier.  List.  Min.  Eng.,  Feb- 
ruary, 1892.     Rec. 


ill! 


416 


KEMP'S  ORE  DEPOSITS. 


gathered  as  float  material.  The  irregular  distrihution,  always 
characteristic  of  the  mineral,  renders  underground  work  uncer- 
tain. Good  ore  should  afford  50%  CrgOs,  and  in  California  no 
ore  less  than  47%  is  accepted.  It  brings  in  the  East  ^tl  to 
$35  per  ton.^ 

2.14.21.  Quebec.  In  the  serpentine  belt  that  extends  from 
northern  Vermont  to  Gaspe,  and  which  contains  the  well 
known  asbestos  mines  near  Black  Lake,  chromite  has  been 
known  for  many  years.  In  1804  some  productive  pockets  were 
found  that  have  since  yielded  about  three  thousand  tons  of  high 
grade  ore.  The  mines  are  two  miles  from  Black  Lake  station, 
and  are  in  a  belt  of  serpentine  south  of  the  asbestos  belt.  In 
the  best  pocket  the  ore  occurred  next  a  dike  of  granulite,"  ac- 
cording to  Donald,  but  elsewhere  it  lacks  this  associate. 

2.14.22.  Newfoundland.  Chroni  e  has  very  recently  bpon 
discovered  and  developed  at  Port  au  Port  Bay,  on  the  west  coast 
of  Newfoundland.  G.  W.  Maynard  states  that  it  occurs  in 
liands  of  serpentine,  which  are  themselves  enclosed  in  diorite. 
The  geological  surroundings  are  thus  those  of  the  usual  ser- 
pentinous  and  basic  igneous  rocks.  The  quantity  exposed  war 
ranted  the  erection  of  a  concentrating  plant, ^ 

COBALT    (see   under  "NICKEL"). 
MANGANESE. 

2.14.23.  Ores:  Pyrolusite  MuOg,  Mn.  G3.2,  braunite,  Mn.O,. 
Mn  (i'.).02.  Some  SiOa,  which  may  be  chemically  com- 
bined, is  usually  present,  and  small  amounts  of  MgO,  Ca(X 
etc.  Psilomelaue  has  no  definite  composition,  but  usually  enii- 
tains  barium  or  other  impurities.  An  Arkansas  variety  lias 
afforded  Brackett  MnO,  77.85. 

'  E.  Goldsmith,  "Chromite  from  Monterej'  County,  Cal.,"  Proc.  Philu. 
Acad.  Sci.,  1873,  305.  Wm.  Irelaii,  Jr..  Reports  of  Cat.  State  Miiicnih- 
gist,  esjiecially  1890,  pp.  KiT,  181),  313,  nm,  583,  ()38.  J.  J.  Cra-.vford  be- 
came State  MineralogLst  in  1892;  Chromite  receives  mention  also  in  his 
rejjorts. 

^  J.  T.  Donald,  "Chromic  Iron  in  Quebec,"  Eiirj.  and  Min.  Jour.,  Sep- 
tember 8,  1894,  224.  M.  Penhale,  Idem,  December  8,  1894,  532.  Win. 
Glenn,  "Chromic  Iron,  with  Reference  to  its  Occurrence  in  Canai la," 
XVIL  Ann.  Rep.  Dir.  U.  S.  Geol.  Surveif,  Part  III.,  2(51.  Rec.  Contains 
a  good  bibliography.     J.  Obolski,  C'a».  Min.  Revieiv,  Jjinuai-y.  1896 

^  Geo.  W.  Maynard,  "The  Chromite  Dejwsits  on  Port  au  Port  Bay, 
Newfoundland,"  Trans.   Anier.  Inst.  Min.  Eng.,  XXVII.  283,  1897. 


THE  LESSER  METALS. 


417 


,  always 
•k  uncer- 
Porniti  no 
t   822   to 

iiids  from 
the   well 

has  been 
ikets  were 
38  of  high 
:e  8tation, 

belt.  In 
ulite,"  HC- 
.te. 

ently  been 
west  coast 

occurs  in 
in  (liorite. 
usual  ser- 
posed  war 


[te,  Mn,0;,. 
^illy  roni- 
|g(),  CaO, 
iually  con- 
lariety  has 

t(>  il/n'<''""'"" 
ni'.vford  lie- 
In  also  in  lii*< 

Jonr..  ^^''P- 

r)32.     Win. 

I  in  Cauiulii." 

Contains 

Port   i^uy. 
1.  1S9T. 


There  are  various  other  oxides  and  hydroxides,  which  are 
rarely  abundant  enough  to  teores.  The  carbonate,  rhodochro- 
site,  and  the  silicate,  rhodonite,  are  rather  common  gangue 
minerals  with  ores  of  the  precious  metals.  Frauklinite  is  also 
an  important  source  (2.07.04).  Pyrolusite  and  psilomelane  are 
the  commonest  ores  the  country'  over,  but  oraunito  is  the  one  in 
the  Batesville  (Ark.)  region.  Manganese  is  widely  dis- 
tributed, and  yet  is  commercially  important  in  but  few  locali- 
ties. It  imitates  limonite  very  closely  in  its  occurrence,  and 
is  often  associated  with  this  ore  of  iron.  To  make  a  manganese 
ore  valuable,  at  least  40"o  metallic  manganese  should  be  pres- 
ent, and  this  is  a  lower  limit  than  was  formerly  admissible 
when  the  ores  were  chiefly  used  in  chemical  manufactures. 
Under  present  conditions,  if  iron  is  present,  the  ore  may  be 
suited  to  Spiegel,  although  even  lower  in  manganese  than 
4(|"(v  Further,  there  should  be  low  phosphorus;  Penrose  says 
not  over  0.2  to  0.25 "o' in  Arkansas,  and  not  over  12/6  SiO^. 
High-grade  ores  run  50  to  (iO*'o  manganese. 

2.14.24.  The  original  home  of  manganese  is  in  the  ferro- 
magnesian  silicates  of  the  igneous  rocks.  In  all  of  them  it  is 
known  to  enter  as  a  minor  base,  acting  much  in  the  same  way 
as  iron.  On  being  released  from  the  ferro-magnesiau  minerals, 
its  subsequent  geological  behavior  is  in  some  respects  much  like 
that  of  iron,  but  it  differ*?  from  iron  in  that  its  sulphides,  though 
known,  are  very  rare  minerals.  Aqueous  circulations  leach  the 
manganese  from  the  igneous  rocks,  whether  deep-seated  or 
superficial,  and  sea-water  has  a  strong  dissolving  effect  upon 
fragmental,  volcanic  ejectments  that  are  thrown  into  the 
ocean.  In  the  latter  case  the  peroxide  of  manganese  finally 
forms  pellets  and  incrustations  on  the  sea-bottom,  especially  at 
S,'n'at  depths;'  in  the  foriner  rhodonite  and  rhodochrosite  result 
as  the  familiar  gangue  minerals  of  many  veins,  and  manganese 
oxide  or  carbonate  enters  into  many  fragmental  sediments  and 
limestones.  Almost  all  the  deposits  of  commercial  importance 
have  been  produced   by  the  subaerial  alteration  of  these  last 

'  For  u  short  review  of  Man.i;anese  in  Nature  see  L.  tie  T-aunay.  Aininlci 
'Irs  MiiivH.  XII.,  l8Ur,  IcS.Vl!)!.  Tiie  sabjeet  is  discussed  at  leu«th  in  Ten- 
msis  Ke}x)rt  on  ilanganese  for  the  Arkansas  Geol.  Survey,  Chai>ter  XXI. 

-  .lolm  Murray,  y^oc.  Roij.  .S'oc,  London,  XXIV.,  538.  Sir  C.  Wyville 
Th.Miison,  The  Atlantic,  II.,  14,  1873. 


i:   .J 


m 


418 


KEMP'ii  ORE  JJEP0iiIT8. 


named,  so  that  nodules  of  manganese  oxides  remain  embedded 
in  residual  clays,  precisely  like  many  brown  hematite  depusits. 
2.14.25.  Example  oU.  Manganese  ores,  chielly  psilomelaue 
and  pyrolusite,  often  in  concretionary  masses,  disseminated 
through  residual  clay,  which  with  the  ores  has  resulted  from  the 
alteration  of  limestones  and  shales.  The  deposits  are  entirely 
analogous  to  P]xr.mple8  'Z  and  'Za,  under  "Iron."  Along  the 
Appalachians  the  favorite  horizon  is  just  over  the  Camliriau 
(Potsdam)  (juartzite.  This  is  the  case  at  Brandon  and  South 
Walliugford,  Vt.,  where  the  ores  occur  in  a  great  bed  of  clay 
between  quartzite  and  limestone.  They  are  referred  to  under 
Example  2a,  where  mention  is  made  of  the  associated  limonites 


section  no.  2. 

sectioTTno.  4. 

Fig.  155. — SecH'Dis  of  the  i'rimora  mnnyamxe  mine,  Virginia.     The  trovf/h  is 
formed  bi/  Potmlam  miidstone  and  ix  filed  with  rliti/  cdrri/iiifj  nodiihs 
of  ore.     Ajter  C.  h\  ll(dl,  Trans.  Anier.  Innt.  Min.  I'-ny., 
XX.,  4H,  J>iue,  1891. 

and  interesting  lignite.  They  have  never  been  important  pro- 
ducers of  manganese.  Crimora,  in  Augusta  County,  Va.,  was 
formerly  the  largest  mine  in  the  couutrj'.  The  containing  clay 
bed  is  very  thick,  as  a  drill  hole,  2' (J  feet  deep,  failed  to  strike 
rock.  The  ores  occur  in  pockets,  which  as  a  maximum  are  .">  to  fJ 
feet  thick  and  20  to  ;{()  feet  long,  and  of  lenticular  sliape. 
Other  irregular  stringers  and  snialler  masses  run  through  the 
clay,  which  preserves  the  structure  of  the  original  rock.  Pots- 
dam quartzite  underlies  it.  Other  similar  bodies  occur  at  Lyii<l- 
hurst  and  elsewhere  in  the  Great  Valley  of  Virginia,  but 
Crimora  is  now  no  longer  a  source  of  ore.     Cartersville,  (xa., 


THE  LEtiHEli  METALS. 


419 


IDEAL  SECTIONS  SHOWING  THE  FORMATION  OF  MANGANESE-BEARINQ 

CLAY  FROM  THE  DECAY  OF  THE  ST.CLaIR  LIMESTONE. 

Boone  Chert  I_^  manqanese-BearinS  Clay  LLJizaro  Limestone 

Saocharoidal  Sanostoni 


E3s 


T.Clair  limestone 


Fia.  1.— Original  Condition  oe  the  Kocks. 


Fki.   !i.-FlUsr  STA(iE.   OF   Dr.CoMPOSITIliN. 


Fio.  3.— Second  Staok  of  Dkcomf'osition-. 


Fra.  4.— Third  Staqe  of  Decomposition. 


Fk;,  156. — Oeological  lieetiona  illuntratiiirj  the  formation  of  the  manganese  ores 

in  Arkansas.     After  R.  A.  F.  Penrose,  Geol.  Survey  of 

Ak:.  1890,  Vol.  }.,  p   177. 


4^0 


KEMrS  QUE  DEPOtilTa. 


38  second  to  Crimora  in  production.  As  at  Crimora,  the  ores 
occur  in  pockets  in  stiff  clay,  and  are  associated  with  (juartzite 
which  is  not  sharply  identified  as  yet.  It  may  he  Canibrian 
(Potsdam),  or  Upper  Silurian  (Medina).  West  of  Cartersville  is 
the  Cave  Spring  region,  where  the  ores  occur  with  Lower 
Silurian  cherts.  There  are  numerous  other  localities  not  yet 
of  commercial   importance  along  the   Appalachians,  in   Ten- 


Fig.  I.jT. — The  I nriicr  mine,  Butestiile  vcyioii,  Arkansas.     Ajttr  li.  A.  F. 
Peiirone,  Geol.  Surwri  of  Ark.,  Is90.  Vol.  T.,  p.  272. 

nessee  and  elsewhere.     Full  descriptions  will  he  found  in  Pen- 
rose's report,  cited  below. 

2. 14. -20.  Batesville,  Ark.  The  ore  is  braunite,  and  is  found 
in  masses  disseminated  in  a  residual  clay  which  was  thought  by 
Penrose  to  have  been  left  by  the  alteration  of  a  limestone  locally 
called  the  St.  Clair.  The  stratigraphy  has  been  reviseil  in 
some  important  particulars  by  H.  S.  Williams,  as  noted  belnv. 
The  St.  Clair  was  regarded  by  Penrose  as  of  geologic  ago  1  • 


TUE  LESSER  METALS. 


421 


loted  bel<Av.     I 


tween  the  Trenton  and  Niagarn  periods.  It  is  underlain  Ijy 
auother  limestone  called  the  Izard,  which  is  later  than  the  Cal- 
ciferous.  On  Penrose's  St  Clair  a  series  of  cherts,  called  the 
Boone  cherts,  is  found,  which  are  of  Subcarboniferous  (IVIissis- 
sippian)  age.  The  clays  are  sometimes  in  valleys,  sometimes 
on  hillsides,  according  to  the  unequal  decay  of  the  limestone. 
South  of  the  Batesville  district  are  the  Boston  Mountains,  a 
range  of  low  hills  500  feet  high,  and  from  these  the  mauganifer- 
ous  rocks  form  a  low  monocline  to  the  north.  The  district  is 
ill  northern  central  Arkansas.  The  ore  was  thought  by  Pen- 
rose to  have  been  derived  from  the  limestone,  and  to  have 
separated  in  its  decay.  H.  S.  Williams  has  niodified  the  above 
stratigraphy  in  important  particulars  by  close  paleontological 
determinations  and  the  modifications  bear  on  the  origin  of  the 
ores  in  a  very  important  way,  changing  them,  as  regards  their 
original  home  from  deep-water  deposits  to  shallow-water  ones. 
Williams  observed  that  the  limestone,  called  the  St.  Clair  above, 
contained  both  a  Lower  Silurian  fauna  and  an  Upper  Silurian 
one.  In  one  good  exposure  on  the  Cason  property  they  were 
separated  !»}'  a  thin  band  of  shale,  which  shale  contained  the 
manganese  ore.  Williams  therefore  restricts  the  name  St. 
Clair  limestone  to  the  Lower  Silurian  (or  Ordovician)  stratum, 
and  calls  the  shale  the  Cason  shale,  and  the  overljing  Upper 
Silurian  (or  Eo-Silurian)  limestone  the  Cason  limestone.  Some 
of  the  clay,  which  was  observed  by  Penrose  to  contain  the 
uodules  of  ore  has  resulted  from  this  shale,  and  it  may  be  that 
the  ore  generally  has  come  from  thesan>e  source.  The  geolog- 
ical relations  would  then  be  closely  parallel  with  Crimora,  Va. 
(H.  S.  Williams,  "Age  of  the  Manganese  Beds  of  the  Batesville 
Region  of  Arkansas,"  Anier.  Jour.  Sci.,  October,  LS!»4,  325.) 
"2.14.27.  Southwestern  Arkansas  contains  a  second  district 
iu  which  the  ore  occurs  in  a  great  stratum  of  novaculite  of 
probable  Lower  Silurian  age.  The  ores  are  of  no  practical  im- 
portance, being  too  lean  and  toodis.seminated.  Small  amounts 
of  manganese  ore  have  been  obtained  in  California,  in  San 
Joacjuin  Count}',  and  from  Red  Rock,  in  San  Francisco  harbor. 
The  former,  and  perliaps  others  in  the  State,  may  prove  impor- 
tant hereafter.  Penrose  has  described  an  interesting  deposit  of 
manganese  ore  near  Golconda,  Nev.  It  is  an  interbedded, 
lenticular  mass  about  150  feet  long  and  10  feet  thick  as  amaxi- 


422 


kemP'h  ore  deposits. 


i 


miiui  in  calcareous  tufa,  of  Pleistocene  age.  It  is  reniarkalilt* 
f ( r  its  content  of  '^i.TH*',,  tungstic  acid.  Penrose  interprets 
it  as  a  superficial  deposit  from  uprising  springs,  wlidsn 
waters  presumably  formed  a  pool,  allowing  of  the  oxidaticm 
and  precipitation  of  the  dissolved  manganese.  The  latter  was 
derived  from  lower  lying  rocks,  presumably  igneous,  althongli 
sediments  are  not  an  impossible  source.'  Leadville,  Colo., 
is  now  an  important  source  of  manganese  ores,  the  shipments 
going  as  far  as  Chicago.  The  geological  relations  are  the  same 
as  for  the  lead-silver  ores,  earlier  described. 

2. 14. '^8.  Considerable  manganese  occurs  at  times  in 
some  of  the  Lake  Superior  iron  ores,  especially  those  from  tlie 
Gogebic  range.  Cuba  has  also  afforded  some  shipments 
notably  high  in  this  metal.  In  the  Santiago  region  the  ere 
forms  nodules  in  the  soil  from  which  it  is  obtained  by  stripping 
and  washing. 

2.14.21).  Quite  productive  deposits  are  found  in  pockets  at 
Markhamville,  Kings  County,  N.B.,  in  Lower  Carboniferons 
limestone.  Some  thousands  of  tons  have  been  shipped.  Otiier 
mines  are  situated  at  Quaco  Head.  At  Tenny  Cape,  in  the 
Bay  of  Minas,  Nova  Scotia,  is  another  deposit  in  Lower  Car- 
boniferous limestone,  which  has  furnished  several  thousand  tuns 
of  ore.     Others  less  important  occur  on  Cape  Breton." 

'  R.  A.  F.  Penrose,  "A  Pleistocene  Manganese  Deposit,"  Jour.  ofGeol.. 
I.,  275.  189:i 

"  "Manganese  Mines  near  Santiago,  Cuba,"  Eng.  and  M in.  Jonr.,  No 
vember  24,  1888,  p.  439.  H.  P.  Brunieil,  "Notes  on  Manganese  in  Canada," 
Amcr.  Gt'oL,  August,  18!)'^.  j).  8().  D.  ile  Cortazar,  "General  Review  of 
Occurrence  and  Manufacture,"  Keps.  and  Au'iirds,  Group  /.,  Ccnh'it. 
Expoitition,  p.  19G.  D.  T.  Day,  Mineral  Resources,  1883,  p.  424;  1883-S4,  |). 
r).")0.  F.  P.  Dui.nington,  "On  the  Fonnation  of  the  Deposits  of  Oxides  of 
Manganese,"  Avier.  Jour.  Sci.,  iii.,  XXXVI.,  175.  Rec.  W.  M.  Fon- 
taine, "Criinora  Manganese  Deposits,"  Tlie  Virginias,  March,  188;5,  iij). 
44-4tt.  Rec.  C.  E.  Hall,  "Geological  Notes  on  the  Manganese  Ore  He- 
lK)sits  of  Criniora,  Va,"  Trans.  Amer.  Inst.  Min.  £»(/.,  June,  1891.  H. 
Halse,  "  Notes  on  the  Occurrence  of  Manganese  Ore,  near-Mulege,  Hiija 
California.  Mexico,'  Trans.  N.  of  Eng.  Min.  and  Mech.  Eng.,  XLI.,  ;!02, 
1892.  H.  Hoy,  "Ores  of  Manganese  anil  their  Uses,"  Proc.  and  Trans.  X. 
S.  Inst.  Nat.  Sci.,  Halifax.  II.,  1804-05,  p.  139.  "  Manganese  Minint;  in 
Merionethshire,  England,"  Eng.  and  Min.  Jour.,  December  18,  188<),  p. 
438.  R.  A.  F.  Penrose,  Ann.  Rep.  Ark  Geol.  Survey,  1890,  Vol.  I.  Tlie 
best  work  published.  Rec.  "Origin  of  the  Manganese  Ores  of  Nortlii'rn 
Arkansas."  etc.,  Amer.  Assoc.  Adv.  Sci.,  XXXIX.,  350.     "The  Chemit-al 


TUE  LEtiHA'Ji  METALS. 


433 


I  renmrkalile 
se  inter}irt't8 

•illgH,     win  ISO 

,he  oxidation 
he  latter  whh 
)U8,  althoiigli 
(Iville,  Coin., 
[le  sliiimieiits 
3  are  the  same 

at  times  in 
hose  from  the 
ne  shipments 
egion  the  (ne 
1  by  stripping 

[  in  pockets  at 
Carboniferous 
ipped.  Other 
1  Cape,  in  the 
a  Lower  Car- 
thousand  tons 
ton.'^ 
"  Jour.  ofOeoL, 


2. 14.  HO.  Panama.  Manganese  ores  have  been  shipped 
iu  large  (juaiitities  from  the  mainland  of  Sonth  America,  just 
cant  of  the  bane  of  the  Isthmus  of  Panama,  although  still  iu  the 
|)rovince  of  that  name.  The  ores  occur  about  ft  to  (!  miles  from 
the  coast  and  H  miles  from  the  dock,  in  the  valley  of  the  Rio 
Viento  Frio.  Great  masses  of  the  oxides  of  manganese  (hoth 
liraunite  and  pyrolusite)  occur  in  residual  clay.  More  or  less 
([iiartz  is  associated  with  them.  The  original  rock  seems  from 
the  very  decomposed  pieces  available  to  have  been  a  clastic 
one,  chiefly  of  feldspathic  fragments.  The  ores  are  rich  in  man- 
ganese and  low  in  phosphorus.  There  had  been  shipped  to  the 
close  of  ISliO,  18,215  tons.' 


§■ 


Relation  of  Iron  and  Manganese  in  Sedimentary  Rocks,"  Jour,  of  GeoK, 
1.,  ;{r)6,  18»:{.  J.  D.  Weeks,  Mineral  Remurc.vn  of  the  U.  S.,  IHS',,  y  d08 
(Kev.):  1H8«,  p.  180;  1887,  j..  144.  D.  A.  Wells,  "  On  the  Distribu'.ion  of 
Manganese,"  ^Iwtcr.  A.ssov.  Adv.  Set.,  VI.,  275.  C.  L.  Whittle,  "(Jenesis 
i)f  the  Manganese  Deposits  at  Quaco,  N.  B.,"  Proc.  Bont.  Soc.  Nat.  Hist., 
XXV.,  p.  2'>:\. 

'  E.  J.  Chibas,  "Manganese  Deposits  of  the  DejKirtnient  of  Panama. 
Iteimblie  of  Colombia,"  Trau.s.  Amer.  IiLst.  Min.  Emj.,  XXVII.,  (CJ,  1897. 
•Hailroad  Building  and  Manganese  Mining  in  Colombia."  Eng.  Mag., 
December.  ISilfi,  Vol.  XII..  42(5.  "Construction  of  a  Light  Mountain 
Railroad  in  the  Republic  of  Colombia,"  'Drans.  Amer.  Soc.  Civ.  Eng., 
XXXVI.,  65,  1896. 


I 


Min.  Jour.,  No- 
nese  in  Canada," 
leral  Review  of 

roup  /.,  Coitcii. 

424;  1888-S4, 1). 

sits  of  Oxides  of 
W.   M.   Fon- 

March,   188H.  pp. 

ganese  Ore  De- 
June,  1891.     H. 

ir  .Mulege,   Haja 

EiKj..  XLI.,  :!i>-'. 

c.  andTraiiii.  X 

mese  Minintr  in 

iber  18,    18SI1.  p. 

i<)0,  Vol.  I.  The 
res  of  Noi-tluTii 
"The  Cheniii'al 


:!l 


'"1 


<l 


f 'I 


'  'i 


CHAPTER  XV. 

THE    LESSER     METALS,     CONTINUED — MERCURY,    NICKEL     AM) 
COBALT,   PLATINUM,  TIN. 

MERCURY. 

2.15.01.  Ores:  Cinuabar,  HgS.  Hg.  80.2,  S.  i;}.8.  Metii- 
cinnabarite  is  a  black  sulphide  of  mercury.  Native  inercury 
also  occurs.  Tiemaunite  the  selenide  HgSe,  and  ouofrito  tlio 
sulphoselenide,  Hg(SeS)  have  been  met  at  Marysvale,  in  south- 
ern Utah.' 

Mercury,  usually  called  (juicksilver  in  commerce,  has  been  dis- 
covered in  workable  quantities  aT.  a  number  of  places  along  the 
Pacific  coast  of  North  America.  Its  chief  localities  are  in  tlie 
Coast  ranges  of  California,  where,  though  formerly  more  prd- 
ductive,  it  is  still  quite  largely  obtained.  The  deposits  extend 
into  Oregon,  but  are  of  no  great  importance.  In  ?mall  amount 
it  has  been  mined  in  Nevada  and  Utah,  and  has  recently  been 
discovered  in  promising  although  not  demonstrated  (lutintity  in 
western  Texas.  Many  localitio;;  are  known  in  Mexico,  but 
Guadalciizar,  in  the  State  of  Ouerrero,  and  Huitzuco,  in  San 
Luis  Potosi,  have  proved  most  productive.  In  South  America, 
the  mines  at  Huancaveiica,  in  Peru,  have  been  in  the  past  of 
vast  productiveness.  In  Europe,  Almaden  in  Spain,  is  much 
the  most  important  of  all  the  deposits  known  to-day,  but  Idiia 
in  Austria,  and  Avala  in  SerA  .i  are  still  of  value.  Several 
other  well-known  mining  districts  of  former  years  have  lapsed 
into  inactivity.  In  Asia  the  great  deposits  of  Kwei-Chau  are 
described  as  being  of  great  possibilities. 

•  G.  J.  Brush  and  W.  J.  Comstock,  "American  Sulpho-selenidea  of  Mrr 
cury,  with  Analyses  of  Onofrite  from  Utah,"  Ainer.  Jour.  Sci.,  April,  IHM, 
312.  G.  F.  Becker  describes  tliis  as  TitMiiannite,  Moiiofjnipli  XIII..  \\ 
385,  U.  S.  Ocol.  Survey,  1H88;  Mineral  Eefiuurees.  1892-5;  Tenth  C't//N'/s. 
XIII.,  463,  1880. 


nil':  LhSS/'Jli  MKTM.S,   CONTINUED. 


42ft 


IICKKL     AM> 


13.8.     Metrt- 

,tive  merouiy 

onofrite  the 

Hie,  in  south- 

,  has  been  (lis- 
ices  along  the 
ties  are  in  the 
rly  more  pi*'- 
eposits  exteutl 
mall  aujoiitit 
recently  been 
B(l  quantity  in 
Mexico,  but 
tzuco,  in   Sail 
)uth  America, 
iu  the  past  of 
psiiu,  is  much 
iiy,  but  Idviii 
>lue.     Several 
■s  ha\e  lapsed 
wei-Chau  are 

selenides  of  MfV 
tii'i..  April,  is^^l. 
njmph  XIII..  \\ 
Tenth   Census. 


2.ir».<i'^.  In  their  f^oologicjil  relations  the  ores  of  (juicUsilver 
are  (piite  invariably  associated  with  igneous  rocks,  although 
the  walls  are  often  sedimentary. 

'^.  1. '■».(»:{.  (I.  F.  Ht'cker' has  recently  given  an  admirable  re- 
view of  (piicksilver  deposits,  the  world  over,  their  mineralogi- 
cal  associates  and  probahle  methods  of  origin,  and  the  same 
subject  has  been  treated  by  A.  Schrauf."  Becker  lias  tabulated 
the  minerals  associated  withciimabar  from  twenty-eight  world- 
wide localities,  and  has  made  it  evident  that  silica,  either  as 
(juartz  or  in  the  opaline  state,  an<l  calcito  are  the  connnon  gaugue 
associates.  Pyrite  or  marcasite  is  almost  invjiriahly  present 
and  bitumen  is  very  widespread.  Varicjus  other  antimony, 
arsenic,  silver,  load,  copper  and  zinc  minerals,  as  well  as  gold, 
are  of  somewhat  irregular  occurrence.  Keeker  reaffirms  his 
previously  cited  theory  of  origin,  that  the  cinnabar  has  come 
up  in  solution  as  a  douhle  sulphide  with  the  alkaline  sulphides, 
but  lays  stress  upon  the  precipitating  properties  of  bituminous 
substances,  which  reactions  were  corroborated  by  experiment. 
He  favors  the  view  that  the  cinnabar  has  impregnated  porous 
or  decon\posed  rock,  ratlier  than  that  it  has  actually  replaced 
it  hy  metasomatic  processes.  The  probable  source  of  tlie  ore 
in  deep-seated  and  widely-distributed  granitic  rocks,  and  espe- 
cially in  such  portions  as  overlie  the  foci  of  volcanic  activity  is 
affirmed. 

2.15.04.  Example  50.  New  Alraaden.  Cinnabar  with  sub- 
ordinate native  mercury,  in  a  gangue  of  crystallized  and  chal- 
cedonic  <juartz,  calcite,  dolomite,  and  magnesite,  forming  a 
stock  work,  or  "chambered  vein,"  in  shattered  metamoriiliic 
rocks  (pseudo-diabase,  psoudo-diorite,  serpentine  and  sand- 
stone). There  are  two  main  fissures,  making  a  sort  of  V,  with 
a  wedge  of  country  rock  between.  The  ore  bodies  are  in  the 
fissures  and  also  in  tlie  intervening  wedge.  They  are  associated 
with  much  attrition  clay.  A  great  dike  of  rhyolite  runs 
nearly  parallel  to  the  fissures,  and  to  this  Becker  attributes  the 
activity  of  circulations  which  filled  the  vein.  The  uprising 
solutions  have  often  been  influenced  by  the  seams  of  clay  and 


■t 


*  G.  F.  Becker,  "Quicksilver  Ore  Deposits,  with  Statistical  Tables," 
Mineral  Resources  of  the  United  States,  1892. 

"A.  Schrauf,  "  Aphorismen  ueber  Zinnober,"  ZeiYs.  fiir  prakt.  Oeol., 
January,  1894,  p.  10.  ' 


^■■■■P 


426 


KEMP'S  ORE  DEPOSITS. 


u 


appear  to  have  especially  deposited  the  ore  along  the  lower 
sides  of  them.  The  ore  has  found  a  lodgment  in  the  crevices 
of  all  sorts  on  the  general  line  of  disturbance,  and  has  im- 
pregnated porous  rocks,  when  they  occurred  in  its  course.  It 
has  been  deposited  simultaneously  with  the  various  gangue 
minerals.  The  wall  rocks  are  of  Neocomian  (Early  Cretaceous) 
age,  but  have  suffered  extreme  meframo'-phism.  Long  after 
this  ceased  came  the  intrusion  of  the  rhyolite,  and  probably 
the  formation  of  the  fissures  now  holding  the  ore.  The  intro- 
duction of  the  ore  was  in  either  Pliocene  or  post-Pliocene  time, 
certainly  not  earlier.  Several  other  mines,  of  which  the  Enri- 
(juita  and   Guadalupe  are    most    important,   are  near   New 


Fig.  158. — Section  of  lite  (Iretit  Wextcrn  cinnabar  mine.     After  G.  F. 
Becker,  Monogrnph  XI II.,  If.  S.  (ieol.  8urm'y,p.  360. 

Almaden,  but  the  New  Almaden  is  much  the  largest  of  all  the 
North  American  deposits  yet  developed.  New  Idria  is  farthor 
south,  high  up  toward  the  summit  of  the  Coast  range.  The 
ore  is  deposited  in  shattered  metamorphic  rocks  of  Neocomiau 
(Lower  Cretaceous)  age,  and  in  overlying  Chico  beds.  The 
ore  is  accompanied  by  l)itumen.  Basalt  is  abundant  ten  miles 
away.  North  of  San  Francisco  other  mines  have  been  opened, 
among  which  are  the  Oat  Hill,  Great  Eastern,  and  Great 
Western.  The  mines  are  in  a  region  pierced  by  eruptions  of 
basalt  and  andesite,  which  doubtless  gave  impetus  to  the  on - 
bearing  solutions.  The  ores  are  deposited  in  both  metamorphic 
and  unaltered  sedimentary  rocks. 


iiiiiiT'iimitMl 


THE  LESSER  METALS,   CONTINUED. 


4a7 


2.15.05.  Example  50a.  Sulphur  Bank.  This  ia  in  the 
same  general  region  as  the  last,  hut  from  its  peculiar  character 
has  been  one  of  the  beat  known  of  ore  deposits.  A  great  flow 
of  basalt  has  come  down  to  the  shores  of  Clear  Lake  from  the 
west.  Waters  charged  with  alkaline  (including  ammonia) 
carbonates,  chlorides,  berates,  and  sulphides,  and  with  COa, 
HaS,  SO2,  and  marsh  gas,  have  circulated  through  it.  Sul- 
phur and  sulphuric  acid  have  formed  at  the  surface,  and  the 
latter  has  dissolved  the  bases  of  the  rock,  leaving  pure  white 
silica  behind.  Lower  down,  cinnabar  is  found,  both  in  the 
basalt  and  in  the  underlying  sedimentary  rocks,  with  other  sul- 
phides and  chalcedony.  Le  Conte  attributed  its  precipitation  to 
cold  surface  waters,  charged  with  sulphuric  acid,  which 
trickled  down  and  met  the  hot  alkaline  solutions.  Becker 
refers  the  same  to  the  ammonia  set  free  toward  the  surface  bj' 
diminished  heat  and  pressure.  The  California  cinnabar  de- 
posits have  been  often,  but  wrongly,  referred  to  vapors  of  the 
sulphide  volatilized  by  internal  heat  and  condensed  above. 

2.15.00.  Example  50/>.  Steamboat  Springs,  Nev.  These 
springs  are  in  Nevada,  only  six  miles  from  the  Comstock 
Lode.  Granite  is  the  principal  rock,  while  on  it  lie  metamor- 
phic  varieties  of  the  Jura-Trias,  and  much  andesite  and  basalt. 
Issuing  through  small  fissures,  the  hot  springs  deposit  chal- 
cedony in  some  places,  carbonates  in  others,  and  cinnal)ar  as 
well  as  gold.  The  following  minerals  have  been  noted  :  "Sul- 
phides of  arsenic  and  antimony;  sulphides  or  sulphosalts  of 
silver,  lead,  copper,  and  zinc;  oxide  and  possibly  sulphide  of 
iron;  manganese,  nickel  and  cobalt  compounds,  and  a  vai-iety 
of  i-he  earthy  minerals"  (Becker).  Becker  thinks  the  source  of 
the  cinnabar  is  in  all  cases  in  the  underlying  granite,  and 
that  it  has  come  up  in  solution  with  sodium  sulphide,  and  has 
been  precipitated  toward  the  surface  bj' the  other  compounds 
in  the  hot  alkaline  waters,  with  which  it  would  remain  in 
solution  at  greater  depths,  temperatures  and  pressures.  The 
Steamboat  Springs  are  often  and  properly  cited  as  metallifer- 
ous veins  in  active  process  of  formation,' 


ill 


W^' 


J. 


'  W.  p.  Blake,  "  Quicksilver  Mine  at  Almaden,  Cal,"  Amrr.  Jour.  Sci., 
ii.,  .KVII.,  488.  (i.  F.  Becker,  "Quicksilver  Deix)sit.s  of  the  Pacific  Sloixi," 
Moiioiji'dith  XIII. ,  U.  S.  Qi'ol.  Survey,  Chap.  17.  Rec.  "On  New  Alma- 
•  leii,"  Cal.  Gcnl.  Survey,  I.,  p.  68.     8.  D.  Christy,  "On  the  Genesis  of  Cin- 


|!!: 


f».  '^l\ 


428 


KEMP'S  ORE  DEPOSITS. 


2.15.07.  Cinnabar  has  recently  been  reported  by  W.  P. 
Blake  from  southwestern  Texas,  in  a  rough,  broken  and  almost 
uninhabited  district  some  10  to  12  miles  from  the  Rio  Grande 
River.  The  cinnabar  occurs  "in  massive  limestone  and  in  a  sili- 
ceous shale,  and  a  white  earthy  clay-like  rock,  and  in  part  in  a 
true  breccia  of  grayish,  white,  siliceous  shale,  dense  and  com- 
pact, imbedded  and  cemented  in  a  red  and  chocolate-colored  fer- 
ruginous mass,  also  dense  and  hard."  The  age  of  the  nearest 
determinable  beds  is  Lower  Cretaceous.  The  quicksilver  ore 
seems  to  impregnate  the  beds,  and  also  to  lie  along  a  shattered  or 
brecciated  belt.  It  is  oftentimes  in  concentric  layers  with  oxide 
of  iron,  with  which  it  seems  to  have  in  general  a  common 
origin,  but  to  have  been  laid  down  in  intervals  of  changed  con- 
ditions of  deposition.  In  addition  to  the  disseminated  granules, 
there  are  bunches  of  soft,  friable  cinnabar  iu  the  shales, 
limestones  and  breccia.  It  is  undemonstrated  as  yet,  whether 
the  deposits  are  workable  or  not.  The  conditions  are  some- 
what hard  because  water  is  lacking,  and  the  location  is  remote.' 

NICKEL   AND   COBALT. 

2.15.08.  These  two  metals  almost  always  occur  together. - 

nabar  Deposits,"  ADicr.  Jour.  Sci.,  June,  187H,  ji.  458;  Eng.  and  Min. 
Jour.,  August  2,  187!),  p.  {\'^.  D.  de  Coitazar,  "General  Review  of  Occur- 
rence, etc.,  of  Merouy."  Rvps.  and  Awards,  Group  /.,  Centeimad  E.rpoxi 
tion,  p.  19(5.  William  Irelan,  Ann.  Reps.  Cal.  State  Mineralogist.  Laur. 
"On  Steanilioat  Springs,"  Aniudcs  de.^  Miiicn.  IHd;?.  4'.2;5.  J.  Le  Conte  and 
Rising,  "Metalliferous  Vein  Formation  at  Sulphur  Yiank."  A)ner.  Jonr. 
Sci.,  July,  1883;  Eng.  and  Min.  Jonr.,  August  2(),  1882,  p.  109.  J. 
Le  Conte,  "On  Steand)oat  Springs,"  Aincr.  Jour.  Sci,  June,  1888,  p.  42-1. 
"Genesi.s  of  Metalliferous  \('ins,"  7(/t'H(,  July.  ISSJ.  J.  A.  Phillii>s. 
"On  Sulphur  Bank,  California,"  Phil.  Mag.,  1871,  ]>.  401;  Quar.  Jonr. 
(h'ol.  Sci.,  XXXV.,  1SV9,  p.  890.  Rolland,  Annahs  f/..s  Mines.  XIV., 
384,  1878.  B.  Silliniiui,  "  Notes  on  the  New  ^vlmaden  Uuicksilver  Jlines," 
Amer.  Jour.  Sci.,  ii.,  XXX VII.,  190.  Sivelcing,  B.  and  H.  Zeitung,  187«, 
p.  45. 

'  W.  P.  Blake,  "Cinnaluir  iu  Texr-,"  Trans.  Amer.  Inst.  Min.  Eng., 
XXV.,  (58. 

'  The  following  genenil  jmpers  on  nickel  and  cobalt  are  important:  1" 
D.  Adams,  "On  the  Igneous  Origin  of  Certain  Ore  Dejtosits,"  Gen.  Min. 
As.Hoe..  Prov.  Quebec,  January  12,  1894.  P.  Argall,  "Nickel:  The  Occur 
rence,  Geological  Distributiou  and  CJenesis  of  its  Ore  Deposits,"  Proc.  Col. 
Sci.  Soe.,  December  4,  1H98,  W.  L.  Austin,  "Nickel:  Historical Sket<-li.' 
Idem,  same  date.    H.  B.  v.  Foullon,  "  Ueber  einige  Nickelerzvorkonunen,  ' 


THE  LESSEE  METALS,   CONTINUED.  429 

Their  ores  embrace  the  following  general  classes:  (1)  Com- 
pounds with  arsenic  and  rarely  with  antimony,  or  with  arsenic 
(or  antimony)  and  sulphur;  {'l)  Sulphur  compounds,  including 
nickeliferous  pyrrhotite  and  pyrite;  (M)  Oxidized  ores,  mostlj' 
hydrated  silicates  related  to  serpentine.'  Although  the  num- 
ber of  minerals  involving  nickel  and  cobalt  is  quite  large,  the 
ores,  properly  speaking,  are  comparatively  few;  nickeliferous 
pyrrhotite  is  much  the  most  important,  especially  as  concerns 
this  country,  but  the  oxidized  ores  may  yet  prove  serious. 
Only  the  ores  {i.e.,  minerals  commercially  important)  are  men- 
tioned in  the  table  below. 

Niccolite NiAs,  Ni.44.06  As.  55. 94 

Millerite NiS,  Ni.(i4.88  S.    35.17 

Linnajite (CoND^S^      Co.21.34,  Ni.30.53    Fe.  3.37     S.    41.54 

Pentlandite....(NiFe)S,  Ni. 34.23    Fe.30.25      S.    33.43 

ttenthite 2Ni0.2MgO,SiO,,6HaO.  Ni  .22.6. 

Garnierite H„0(Ni,Mg)O.Si02+iH50  Ni.25.0. 

Zamtite Ni'c03,2Ni(OH) ^+Ai\^6   Ni.46.8. 

To  these  nickeliferous  pyrrhotite  and  pyrite  should  be  added, 
the  former  being  the  most  important  of  all. 

^.lo.O'.i.  Niccolite  was  reported  years  ago  at  Tilt  Cove,  New- 
foundland, in  some  quantit}',  but  elsewhere  has  not  been  found 
in  any  serious  amount  in  North  America.  It  also  occurs  in 
some  of  the  western  openings  of  the  Sudbury  district.  Millerite 
furnished  a  small  portion  of  the  nickel  at  the  Gap  Mine,  Penn- 
sylvania, as  noted  below.  Linnjeite,  variety  siegenite,  occurs  in 
a  sandstone  bed  at  Mine  la  Motte  in  disseminated  octahedra, 
and  although  small  attempts  have  been  made  to  utilize  it,  the 
anion nts  are,  so  far  as  known,  not  large  enough  for  success. 
Peutlandite  must  be  mentioned  together  with  nickeliferous 
pyrrhotite.  It  has  been  somewhat  of  a  question  among  min- 
eralogists in  just  what  relations  tiie  nickel  occurs  in  pyrrhotite; 

.Inhrlmchd.  k.  k.  ijcol.  Rcich-saustaU,  Vienna.  XLII.,  223,  18!)2.  D.  Levat, 
Annnlcsdrs  Miiim,  1S!»2,  l»art  II.  J.  II.  L.  Vogt,  "  Nikkelforkonister  og 
Xikkelproduktion  "  (Occurrence  ami  Production  of  Nickel),  Noriveyian 
(icol.  SiiriYi/.  Kristiania,  1^92;  a  resume  in  (iernian  accompanies  tlie 
paper.  "Sulphidisclie  Aussclieidungen  von  Nickelsidpliiderzen,"  etc., 
Ziits.  fiir  pmkt.  (leol.,  April,   18113,  12."). 

'  This  is  i)ractically  tlie  same  grouping  that  is  given  by  J.  H.  L.  Vogt, 
Zcits.  filr  prakt.  Geol.,  April,  1803,  125.  See  also  P.  Argall,  Proc.  Colo. 
Sci.  Soc,  December  4,  181)4. 


f]   wt'^^ 


430 


KEMP'S  CUE  DEPOSITS. 


whether  replacing  the  iron  in  Fe7SH,  or  some  other  variety  of 
FenSn+i,  to  the  extent  of  a  fraction  of  one  per  cent,  up  to  five, 
or  whether  there  is  an  isomorphous  or  distinct  nickel  or  iron- 
nickel  sulphide  intermingled  with  the  pyrrhotite.  As  far  back 
as  184;$  Seheerer  identified  peutlandite  from  southern  Norway, 
and  several  other  related  minerals,  such  as  polydymite,  have 
been  less  definitely  described.  More  recently  it  has  been  shown 
that  the  nickel-rich  portions  of  the  pyrrhotitic  ores  are  (juite 
feebly  magnetic,and  processes  have  even  been  suggested  for  con- 
centrating the  nickel  based  on  this  principle/  Pentlandite  is 
non-magnetic,  and  possibly  this  mineral  in  very  fine  dissemina- 
tions may  contribute  of  its  richer  percentage  of  nickel  to  raise 
the  total  of  the  pyrrhotites  as  mined.  Some  nickel,  however, 
always  remains  in  the  strongly  magnetic  residues,  so  that  we 
are  not  yet  justified  in  abandoning  the  earlier  view  that  this 
metal  replaces  some  of  the  iron  of  the  pyrrhotite.  Pyrrhotite 
is  the  chief  ore  at  Sudbury,  and  was  the  ore  at  the  Gap  Mine. 
Pennsylvania,  until  the  workings  were  dismantled  in  181)4. 
In  southeast  Missouri,  but  more  especially  at  Mine  la  Motte, 
nickeliferous  pyrite  accompanies  the  galena  (see  ^i.Oo.OD),  and 
has  furnished  a  considerable  amo-..it  as  a  by-product  in  the 
metallurgy  of  lead.  Of  the  oxidized  ores  it  is  not  easy  to  speak 
as  regards  their  individual  importance.  The  hydrated  silicates 
are  of  extremel}^  variable  composition,  and  while  one  or  two 
illustrations  of  the  type  are  selected  for  the  table,  no  one  of 
them  is  yet  seriously  mined  in  America. 

2.10.10.  Example  16c.  (See  -^.0:5.10  and  2.04.02.)  Pyr- 
rhotite Beds  or  Veins.  Lenticular  masses  of  pyrrhotite 
interbedded  in  gneisses  and  schists  as  described  for  pyrite 
They  are  known  at  various  places  in  the  Ea^t.  Openings  have 
been  made  at  Lowell,  Maes.,  Chatham  and  Torriagton,  Conn., 
and  on  the  mountain  on  the  east  bank  of  the  Hudson,  called 
Anthony's  Nose."    The  last  is  much  the  largest  of  those  named, 

'  See  in  this  connection  D.  H.  Browne,  " On  the  Sudbury  Ores,"  £«(/. 
and  Mill.  Jour.,  December  3,  1893.  Rec.  S.  H.  Enimens,  "The  Consti 
tutioii  cf  Nickeliferous  Pyrrhotite."  Jonr.  Amcr.  Chem.  Soc,  XIV.,  No.  10. 

"  H.  Credner,  Beiy.  nud  Huctt.  Zeit..  lHO(i,  p  17.  Dana'.s  Treatise  on 
Mineralogy,  (ith  Edition,  under  Pyrrhotite,  gives  several  analyses  from 
Putnam  County,  N.  Y.  J.  F.  Kemp,  "  The  Nickel  Mine  at  Lancaster  (irai>, 
Penn,  and  the  Pyrrhotite  Deposits  at  Anthony's  Nose,  on  the  Hudson," 
Tnim.  Amer.  Inst.  Min.  Eng.,  XXIV.,  020  and  8S3. 


THE  LESSER   METALS,   CONTINUED. 


431 


and  though  never  mined  for  the  nickel  which  is  known  to  be 
present,  it  was  utilized  as  a  material  for  sulphuric  acid  fumes 
during  the  ten  years  succeeding  IHOS.  The  geological  relations 
give  it  especial  interest.  The  ore  body  is  entirely  analogous  to 
the  magnetite  lenses,  which  are  not  rare  in  the  Highlands  of 
the  Hudson.  It  lies  in  a  light-colored  gneiss,  conformably  to 
the  laminations,  and  must  have  attained  20  or  '60  feet  in  thick- 
ness. It  has  been  mined  down  :5()0  or  400  feet,  and  apparently 
for  50  feet  or  more  on  the  strike.  About  100  yards  west  is 
found  a  basic  gneiss,  consisting  of  green  hornblende  and 
plagioclase,  with  a  little  biotite.  The  wall  rock  contains 
quartz,  plagioclase  and  very  subordinate  hornblende.  In  the 
thin  section  it  appears  fullj'  as  acidic  as  a  (juartz-diorite. 

Much  hornblende  is  associated  with  the  pyrrhotite,  and  occa- 
sional lunipa  of  magnetite,  with  which  are  found  titanite  and 
apatite.  The  ore  j'ielded  about  2^%  sulphur  as  used  for  .years 
in  the  chemical  works,  and  was  especially  prized  because  it 
contained  no  trace  of  arsenic.  The  geological  relations  give  no 
reason  for  regarding  the  ore  body  as  a  basic  segregation  of  a  gab- 
broic  magma,  but  quite  the  contrary.  Several  of  the  magne- 
tite mines  in  this  region,  it  may  be  added,  are  troubled  with 
pyrrhotite  in  the  ore,  but  whether  it  is  nickeliferous  has  not 
been  determined.^ 
Similar  pyrrhotites,  low  in  nickel,  occur  in  Ontario.'' 
3.15.11.  Example  i;3(t.  Gap  Mine,  Penn. ;  Sudbury,  Out. 
Bodies  of  nickeliferous  pyrrhotite  and  chalcopyrite  with  verj* 
subordinate  pyrite,  in  the  outer  portions  of  intrusions  of  basic 
igneous  rocks,  which  may  be  metamorphosed  to  amphibolites. 
Cobalt  is  present  in  less  amount  than  nickel  and  varies  much 
in  its  relative  proportions.  Secondary  millerite  sometimes 
forms  in  cracks,  as  do  quartz,  siderite  and  one  or  two  other 
minerals,  but  in  variety  of  species  ore  bodies  of  this  type  are 
exceptionally  barren.  The  type  is  of  world-wide  distribution, 
as  noted  by  Vdgt,  and  is  well  known  in  Norwaj',  Sweden  and 
one  or  two  ether  European   localities.     The  number  of  the  Ex- 


1 

f 

i 

;. 

\m 

1  l' ;; 

', 

'  W.  H.  Hoffman,  "  The  late  Discovery  of  Large  Quantities  of  Magnetic 
and  Nonmagnetic  Pyrites  in  the  Croton  Magnetic  Iron  Mines,  N.  Y.," 
Tnins.  Amer.  Iin<t.  Miii.  Eng.,  June,  lHi»2.  J.  C.  Sniociv,  Ihilhtiii  of  New 
)'ork  State  Museum,  Dunderberg  Mine,  p.  18:   Hobby  Opening,  p.  24. 

'  F.  D.  A.lams,  Cfeol.  Survey  Canada.  Vol    VI.,  18yi-{)3,  Part  J. 


II 


432 


KEMP'S  ORE  IJEPOISITS. 


ample  indicates  its  genetic  parallelism  with  the  titaniferous 
magnetites  of  *-i.o;}.ll. 

2.15.12.     The  Gap  Mine,  in  Lancaster  County,  southeast- 
ern Pennsylvania ,'  was  originally  opened  for  copper  in  the  pre- 
ceding century.     The  copper  enterprises  were  all  failures,  and 
not  until  in  the  fifties  was  the  presence  of  nickel  recognized. 
The  mine  then  became  the  largest  single  producer  of  its  day, 
and  remained  active  until   1  Hit:},  since  which  time  it  has  been 
abandoned.     As  shown  in  the  accompanying  map  and  sections 
a  lenticular  outcrop  or  mass  of  greenish   black   rock,   about 
2.000  feet  in  length  and  500  feet  as  a  maximum  width,  is  found 
in  the  midst  of  mica  schist,  and  apparently  conformable  to  the 
laminations.     It  strikes  nearly  east  and  west,  and  is  contracted 
along  the   section   AA,    where   it   was   most   productive.     It 
seemed  to  pinch  in  somewiiat  in  depth,  so  far  as  the  workings 
extended  (about  250  feet).     The  ore  was  chiefly  found  at  the 
eastern  end  of  the  lense,  and   was  much  less  abundant  where 
followed  to  the  westward  on  the  south  side  with  a  drift,  as  far 
as  is  colored  black.     Prospect  holes  still  further  west  proved 
the  presence  of  the  amphibolite,  but  failed  to  show  ore.     A 
dike  of  olivine-diabase  of  the  familiar  Triassic  sort  common  in 
southeastern  Pennsylvania  outcrops  about  1.500  feet  southeast, 
but  it  is  much  later  in  time  than  the  amphibolite,  with  which 
and  u  ith  the  ore  it  has  no  apparent  connection.      The  ore  is 
pyrrhotite  in  far  the  largest  amount,  but  when  cut  in  thin  sec- 
tions along  with  the  containing  amphibolite,  it  is  seen  under 
the  microscope  that  a  light  yellow  mineral,  presumably  pyrite, 
is  mixed  all  through  the  bronze-colored  pyrrhotite.     The  ore  is 
richest  near  the  contact  and  fades  into  lean  disseminations  as 
this  is  left.     The  lense  consists  in  far  tlie  largest  part  of  green 
hornblende  of  the  common  variety,  quite  pale  in  thin  section, 
and  with  pleochroism  from  green  to  yellow.     Many  specimens 
are  formed  of  this  and  nothing  else,  except  scattered  grains  of 


*  P.  Fiaser,  "Report  CCC,"  Second  Pfun.  Geol.  Survey.  A  geologicjil 
desc'ri|)ti()ii  and  Iiistorical  sketcliare  given,  and  also  an  outline  map  in  tlic 
accompanying  atlas,  on  which  the  figure  here  used  is  based.  The  descrip 
tion,  liowever.  gives  the  impression  that  the  ore  is  millerite,  and  hardly 
mentions  pyrrhotite,  whereas  the  millerite  is  a  com])aratively  rare  niin 
eral.  Joseph  Wharton,  "Analysis  of  the  Nickel  Ore  from  the  Gap  ^linr 
Lancaster  County,  Penn.,"  Pruc.  Phila.  Acad.  Sci.,  18T0,  p.  0. 


» •vrmm  \ 


itaniferous 

sontheast- 
in  the  pre- 
ihires.  aud 
eoognized, 
of  its  (lay, 
t  has  been 
k1  sections 
)ck,  about 
h,  is  found 
able  to  the 
contracted 
iictive.     It 

workings 
Hind  at  the 
lant  where 
rift,  a8  far 
est  proved 
w  ore.  A 
3ommon  in 
southeast, 
vith  whicli 
The  ore  is 
in  thin  sec- 
seen  under 
ibly  pyrite. 

The  ore  is 
inations  as 
irt  of  green 
lin  section. 

specimens 
1  grains  of 

A  geologii'iil 
le  map  in  tin' 
The  descrip 
i,  and  hardly 
sly  rare  iiiii! 
lie  Gup  Mill!'. 


434 


Kh'AfP'ii  CllK  Dtn'Ot^lTS. 


pyrrhotite.  Others  show  a  little  jilagioclaso,  and  a  few  flakes  cjf 
biotite.  Recognizable  remains  of  orthorhonibic  pyroxene  and 
olivine  were  detected  despite  the  general  and  thorough  meta- 
morphisni  of  the  rock.  No  more  accurate  name  can  be  given 
it  than  ampliibolite,  although  there  is  little  doubt  that  it  origi- 
nally was  a  very  basic  gabbro  or  pyroxenite.  The  ore  contains 
considerable  secondary  millerite,  which  forms  crusts  on  tlio 
cracks  of  pyrrhotite,  and  often  veins  and  stringers  of  quartz 
traverse  it.  In  vuggs  in  these,  beautiful  crystals  of  vivianite 
are  rarely  met.  The  close  parallel  that  the  ore  body  affords  in 
its  geology  to  several  Norwegian  mines  figured  by  Vogt  in  the 
Zeitschrift  fiiv  prakt.  Geologie,  April,  l.S'i.'),  Plates  V.  and 
VI.,  is  very  striking.  (See  especially  Meinkjilr  GrubenfeM. 
Fig.  3  of  Plate  VI.)  The  views  of  Vogt  on  the  origin  of  such 
ore  bodies  by  differentiation  of  a  basic  igneous  magma  in  cool- 
ing, and  by  concentration  of  the  early  crystallizations  at  the 
contacts,  according  to  Soret's  principle,  were  outlined  earlier 
in  the  discussion  of  the  table  of  classification  of  ore  deposits. 
In  a  metamorphosed  rock,  such  as  the  Gap  amphibolite,  there  is 
a  leasonable  groimd  for  regarding  the  ore  as  a  contact  deposit 
due  to  deposition  from  solutions,  but  after  seeing  the  larger, 
less  metamorphosed  but  otherwse  closely  analogous  ore  bodies 
of  the  Sudbury  district,  the  writer  (J,  F.  Kemp)  sees  no  escape 
from  the  conclusion  that  they  and  it  are  original  crystalliza- 
tions from  the  igneous  magma  as  much  as  any  other  component 
minerals  of  the  intruded  mass.' 

2.15.i;j.  The  Sudl)ury  nickel  mines  are  of  quite  recent  de- 
velopment, as  the}'  were  opened  in  188(1,  although  discovered 
earlier.  They  are  situated  forty  miles  north  of  Georgian  Bay, 
an  arm  of  Lake  Huron,  and  on  the  eastern  portion  of  the  original 
Huronian  belt.  The  Laurentian  granites  and  gneisses,  which 
to  the  east  form  a  vast,  monotonous  stretch  of  low  glaciated  hil- 
locks and  swamps,  are  covered  near  Sudbury,  and  for  a  bundled 
miles  west,  by  a  great  area  of  later  Huronian  sediments  (gray- 

'  Literature  on  the  Gap  Mine,  W.  P.  BlaJie,  Mineral  Rcsnitrces,  ISNi.  p. 
8!)9.  J.  Eyerman,  "Mineralogy  of  Pennsylvania,"  P.  Fraser,  Report  r< '('. 
Second  Peuu.  Geol.  Sarvei/,  p.  Uhi.  J.  F.  Kemp,  'The  Nickel  IMine  ;it 
Lancaster  Gap,  Penn,,  and  the  Pyrrhotite  Deposits  at  Anthony's  N<isi',  ou 
the  Hudson,"  Trans.  Avier.  Inst.  Min.  Eng..  XXIV.,  620,  883,  1884.  J. 
Wharton,  "Analysis  of  Nickel  Ore  from  the  Gap  Mine,'  Proc.  Plula 
Acad.  Sci.,  1870,  p.  6. 


THE  LESSER  METALS,   CONTINUED. 


435 


wackea,  quurtziteH,  8chiHt8)an(l  by  inimeuseiutrusious and  dikes 
of  norites  aud  more  acid  rocks,  at  times  more  or  less  metamor- 
phosed; eruptive  breccias  and  other  interesting  varieties  too 
numerous  to  cite  in  detail  are  also  present    The  geology  is  very 


3 


ij  ., 


H  I 


H 


2z 


n 
so 

n  ■ 


o> 


^  > 


M^ 


5^ 


li 

s 
I 

5 


W 


w  Ci  •  ■•  -  ■) 

P  2  I  ^\ 


o 

W  O 
r)  r 


a 

Ah 


-la 


complex,  and  is  in  large  part  concealed  by  swamps  and  almost 
impenetrable  tliickets.  It  is  evident,  however,  that  several 
great  intrusions  now  identified  as  norite  run  northeast  and 
southwest  through  the  Huronian  area.     One  on  the  southeast; 


' 


436 


KEMP'S  ORE  J) K POSITS. 


f 


has  along  its  own  southeaHtern  side  some  rich  deposits,  includ- 
ing the  Evans,  Copper  Cliff,  Stobie  and  Blezard.  The  Evatis 
is  on  a  small  outlier  from  the  main  mass,  and  the  Stobie  and 
Blezard  are  further  in  from  the  actual  contact  than  is  the  Cop- 
per Cliff.  Some  miles  west  of  tho  great  diorite  dike  just 
referred  to  is  the  large  Murray  mine  in  another  intrusion,  with 
a  stretch  of  supposed  Laurentian  granite  between.  Sonio 
twenty  miles  southwest,  and  in  connection  with  a  still  differ- 
ent diorite  dike  are  found  the  Worthington  mine  and  several 
undeveloped  openings  in  Drury  and  Denison  townships. 
About  the  same  distance  northwest  of  Sudbury  is  a  region 
around  Wahnapitae  Lake,  well  thought  of,  but  not  yet  produc- 
tive. 

3.15.14.  In  a  recent  valuable  paper^  T.  L.  Walker  has 
traced  out  the  petrographical  character  of  the  basic  iutrusives 
that  conbiin  the  ore.  In  crossing  th^  dikes,  the  rock  in  its 
unmetamorphosed  condition  remote  from  the  contacts  is  h 
norite.  As  the  edge  and  therefore  the  ore  body  are  approached, 
the  hypersthene  changes  to  bastite,  and  finally  in  the  mines  to 
hornblende,  which  has  occasioned  the  use  of  the  name  diorite. 
Titanife.ous  magnetite  accompanies  the  ore,  and  has  been 
observed  enclosed  in  it.  Walker  concludes  that  the  sulphides 
have  crystallized  directly  from  the  fused  magma,  just  as  have 
the  usual  components  of  an  igneous  rock.  It  would  seem  that 
the  change  of  hypersthene  to  hornblende  at  the  borders  woidd 
indicate  some  considerable  metamorphism  apparently  dynamic 
in  its  nature. 

2.15.15.  The  ore  bodies  betra}''  their  presence  by  great  out- 
crops of  rusty  gossan,  consisting  of  limouite  in  layers  and  cellu- 
lar masses,  which  have  resulted  from  the  decay  of  the  pyrrhotite 
and  chaloopyrite.  The  outcrop  of  this  gossan  may  run  with 
local  interruptions  for  long  distances.  When  it  was  penetrated 
in  the  early  prospecting  the  chalcopyrite  lying  below  attracted 
attention,  and  the  deposits  were  regarded  as  copper  mines. 
Later  the  presence  of  the  nickel  in  the  pyrrhotite  was  recog- 
nized, and  the  nickel  became  the  principal  object.  The  two 
ores  are  inseparablj'  intermingled  and  themselves  form  irregular 
masses  often  of  great  size  in  the  diorite.     It  is  stated  by  Peters 

"  T.  L.  Walker,  "  Geological  and  Petrographicul  Studies  of  the  Sudbury 
^"ickel  Disti-ict,  Canada,"  Quar.  Jour,  of  the  Geol.  Soc,  1897,  40. 


m 


*•:. 


lits,  inclnd- 
The  EvHtis 
Stobie  Hixl 
is  the  Cop- 
3  dike  jtist 
msion,  with 
)en.  Soino 
,  Htill  (liffer- 
aml  several 

townshijw. 

is  a  region 
;  yet  produc- 

Walker  has 
ic  iutrusives 
3  rock  in  its 
ontacts   is  a 

I  approached, 
the  mines  to 
[lame  diorite. 

II  d  has  been 
the  sulphides 

just  as  have 
Id  seem  that 
orders  would 

itly  dynamic 

Iby  great  out- 
ers and  celhi- 
Ihe  pyrrhotite 
pay  run  with 
as  penetrated 
>w  attracted 
)pper  mines. 
was  reoog- 
±     The  two 
)rm  irregular 
ied  by  Peters 
jof  the  Sutlbm-y 


1 

1^ 

Fios.  161  AND  163. — View  of  the  Copper  Cliff  Mine,  near  Sudbunj,  Ontario. 

The  mine  is  in  diorite.     The  ridc/e  nt  tlie  Ixirkfjroitnd  is  granite. 

From  jihotographs  by  1\  G.  White,  lUdi. 


I 


ii 


1? 

1 
I 

i 

t: 

ii 
t; 

SI 

tl 

SI 
01 

II 
ai 
ai 

D( 

e\ 

so 

So 

it 
m 
ce 

ii)' 

ro( 

sei 

1 

2!)r 


TllK  JJ'JSSEIi  MKTAL8,   CONTIA'UKJJ. 


43: 


thftt  the  early  work  at  tlie  Stobie  showed  ore  over  100  feet 
across.  The  diorite  is  a  dense  bhick  roc-k  resenibliug  most 
closely  black  bawilt  in  its  appearance.  Quite  pure  pieces  of 
sulphitles  of  large  size  are  at  times  obtainud,  but  practically  all 
the  ore  contains  rock  up  to  3«)%  or  more  of  its  weight,  ami  the 
sulphides  form  irregular  masses  in  it.  Great  lieaps  of  rock  too 
lean  to  work,  but  showing  bits  of  sulphides  through  the  pieces, 
are  thrown  out  o!i  the  <lunipH.  The  workings  are  in  the  form 
hoth  of  open  cuts  and  of  shafts,  from  which  the  drifts  wander 
(lut  somewhat  irregularly  in  searcli  of  the  ore-masses.  While 
it  is  truly  said  the  ores  favor  the  contacts,  this  should  not  be 
too  closely  interpreted.  The  mines  and  the  gossan  do  lie  along 
the  outer  portions  of  the  diorite  masses,  yet  as  now  mined  at 
all  the  large  producers  they  are  entirely  in  the  diorite,  and  often 
very  considerable  distances  from  the  actual  contact,  of  which 
no  evidence  appears  from  the  workings.  Included  masses  of 
granite  occur  with  the  ore  at  Copper  Cliff,  and  as  a  general 
thing  have  a  rim  of  chalcopyrite.  Some  small,  secondary  and 
insignificant  quartz  veins  ramify  through  the  diorite,  and  con- 
tain chalcopyrite  and  some  })yrrhotite,  both  of  which  are 
secondary,  but  they  are  trifling  in  amount.  On  the  contrary, 
the  masses  of  the  sulphides  are  irregularly  distributed,  often  as 
small  isolated  bits,  throughout  the  fresh,  dense  diorite,  and  leave 
one  no  reasonable  alternative  but  to  conclude  that  they  are  as 
much  an  original  crystallization  from  the  igneous  magma  as 
any  other  of  the  minerals  in  the  rock.  Evidence  of  disturb- 
ance has  been  found  in  the  region,  and  apparent  fault  lines  are 
not  lacking,  but  the  great  open  cuts  of  the  mines  show  no 
evidence  of  them.  The  method  of  igneous  origin  has  been 
somewhat  attacked.  Posepuy,  for  example,  refers  to  it  as 
something  extraordinary  when  in  his  great  essay  on  "The 
Genesis  of  Ore- Deposits,"  he  cites  Vogt's  work,  and  controverts 
it  strongly ;  but  it  appears  to  the  writer,  after  having  seen  the 
mines,  that  no  process  of  solution  and  replacement  can  be  con- 
ceived of  as  introducing  these  scattered  masses  of  sulphides 
into  dense,  undecomposed  and  apparently  unbroken  igneous 
rock,  which  would  not  strain  the  faith  of  a  conservative  ob- 
server to  a  far  greater  degree.* 

'  D.  H.  Browne  gives  in  tlie  School  of  Minen  Quarterly  for  July,  1895  p. 
2ilT,  a  very  suggestive  paper  on  "  Segregation  in  Ores  and  Mattes."    The 


i| 


438 


KEMPS  ORE  JJEPOSITJS. 


ffl 


! 


•^.15.16.  It  is  an  interesting  fact  that  sperrylite,  the  unique 
arsenide  of  platinum,  occurs  in  the  Sudbury  region,  but  was 
not  first  discovered  in  a  nickel  mine.  Traces  are,  however, 
said  to  occur  in  the  nickel  ores.  Cobalt  is  in  comparatively 
small  amount,  much  less  than  in  some  other  nickel  regions. 
The  ores  vary  In  richness  in  different  mines  and  in  different 
parts  of  the  same  mine.  They  run  from  over  1%  to  over  5% 
nickel,  and  have  a  copper  percentage  somewhat  under  the 
nickel.  The  Worthington  has  yielded  a  little  gersdorffito 
(NiAsS),  and  niccolite  (NiAs)  in  secondary  quartz  veins,  and 
a  vein  is  reported  from  Deuison  township  containing  both 
these.  A  galena  vein  is  reported  from  the  same  region,  and  a 
little  millerite  is  said  to  have  been  found  in  the  Copper  Cliff 
mine.  Traces  of  zinchleude  have  also  been  noted  in  some  of  tlie 
ores,  but  aside  from  these  the  mineralogy  is  limited  to  the  two 
principal  sulphides.' 

^.16.17.  Example  4Ua.  Riddle's,  Douglass  County,  Ore- 
gon. Irregular  deposits  of  hydrated  silicates  of  nickel  and 
magnesia,  in  serpentine  formed  by  the  alteration  of  peridotites 
or  related  rocks.  Limonite,  chalcedonic  quartz  and  chromito 
are  quite  invariable  associates,  as  are  clays  and  other  products 

results  o'i  ii  long  experiencf  with  mattes  sliow  tliut  in  the  matte  pot  tlic 
coppiT  tends  to  collect  at  the  top  and  sides,  the  nickel  in  the  center. 
Parallels  are  drawn  with  the  ore  bodies,  in  the  central  parts  of  which  the 
nickel  is  in  excess  of  tlie  •f^n])er,  while  at  the  edges  the  copper  exceeds 
the  nickel. 

'  On  Sudbury  .see  F.  D.  Adams.  "The  Igneous  Origin  of  certain  Ore 
Deposits,"  General  Miii.  A.ssoc,  Prov.  Qiiehee,  January  12,  1894.  A.  E. 
Barlow,  "The  Nickel  and  Copper  Deposits  of  Sudbury.  Ont,"  Offaint 
Natnr((lint,  June,  lHi)l.  K.  Bell,  (icol.  Sitrrei/  of  Can.,  1S!)0-!»1 ;  F.  o,  !i|. 
Bull.  Geol  Soc.  Amer.,  II.,  p.  12.").  T.  G.  Bonney,  "  Notes  on  a  part  of  the 
Huronian  Series  near  Sudbury,"  Qnar.  .Jour.  Geol.  Soc.,  XLIV.,  'I,  IHXS, 

D.  N.  Browne,  £n(j.  ((nd  Miii.  Jour.,  September  Ki  and  December  2,  181»:!. 

E.  R.  Bush,  "The  Sudbury  Nickel  Region,"  Mem,  :\Iarch  IT,  1894,  p.  241 

F.  W.  Clarke  and  O.  Catlett.  •  Platiniferous  Nicki'l  Ore  from  Canada," 
Amer.  Jour.  Sei.,  iii.,  XXXVII.,  ;{72.  J.  H.  Collins,  "Note  ou  the  Sud- 
bury Copper  Deposits,"  Qnar.  Jonr.  Geol.  Soc.,  XIJV.,  834.  J.  Gamier. 
"Mines  du  Nickel,  Cuivre  et  Platine,  du  Di.strict  du  Sudbury,"  MemoircK 
(le  la  Sociefie  (h'N  Ingeniritr.s  ('/r//.s-.,  Paris,  March,  1891.  VV.  H.  Merritt. 
Trans.  Amer.  Inst.  Min.  Enij.,  XVII.,  29.").  E.  D.  Peters.  "On  Sudbury 
Ore  Deposits."  Idem,  October,  1889;  Eng.  and  Min.  Jour.,  October  2ii, 
18H9.  Berg.  u.  Hnetl.  Zeit.,  I  ,,  149,  1891.  Mineral  Resources  ofjhe  U.  S.. 
]S88,  110. 


THE  LESSER  METALS,   CONTINUED. 


439 


:he  unique 
a,  but  WHH 
,  however, 
iparatively 
el  regions, 
in  different 
to  over  5/0 
under  the 
gersdorffite 
5  veins,  and 
lining   both 
igion,  and  a 
'opper  Cliff 
some  of  the 
:l  to  the  two 

lounty,  Ore- 
nickel  and 
f  peridotites 
tid  chromite 
ler  products 

matte  pot  the 
111  the  center. 

of  which  tlu! 

p])er  exceeds 


of  alteration.  The  ore  occurs  in  loose  bo  ilders  on  the  surface, 
and  as  a  coating  on  the  walls  of  small  cracks  and  vemlets  that 
penetrate  the  more  massive  serpentine.  The  largest  deposits 
of  this  character,  so  far  as  yet  opened  in  this  country,  are  in 
the  Coast  range,  southwest  of  Riddle's  Station,  Douglass 
County,  Oregon,  on  the  Oregon  and  California  Railroad. 
The  mines  occur  on  a  steep  hillside  in  serpentme  that  has  re- 
sulted from  the  alteration  of  the  ^v  .lety  of  peridotite,  called 
harzburgite,  i.e.,  bronzite  and  olivine.  Open  cuts,  small  drifts 
and  test  pits  have  served  to  show  the  nickel  silicates,  richest  at 
the  outcrop  and  fading  out  into  small  veinlets  and  reticulations 
in  depth,  until  beyond  t'le  zone  of  superficial  decay,  they  disaj)- 
pear.  The  openings  are  still  in  the  condition  of  prospects,  and 
productive  mining  is  yet  to  be  begun.  The  nickel  has  been 
shown  bj'  J.  S.  Diller  to  have  been  derived  from  the  olivine 
of  the  rock,  as  chemical  analysis  of  this  mineral  indicated 
O.:2(!,*'o  NiO  By  the  familiHr  and  ready  alteration  of  the  oliv- 
ine the  nickel  has  separated  as  the  silicate,  and  has  finally 
been  concentrated  sufficiently  to  be  noticeable.'  At  Webster, 
in  North  Carolina,  are  surface  deposits  of  nickel  silicate  which 
have  attracted  attention.  They  occur  in  the  variety  of  perido- 
tite, which  is  chiefiy  olivine,  and  is  called  dunite.  The  geo- 
logical relations  and  origin  are  i)ractically  the  same  as  those 
in  Oregon,  just  cited.  The  mines  are  not  yet  i)roducers."^ 
Green  crusts  of  oxidized  nickel  compounds  have  been  found 
with  the  chromite  in  the  town  of  Texas,  Penn.,  but  are  of  no 
practical  importance.  Such  superficial  discolorations  are  \Qvy 
common  in  serpentinous  districts,  but  it  is  a  curious  fact  that 
they  are  notably  lacking  in  the  dioritic  varieties  of  Example!. '5a. 
The  greatest  deposits  in  serpentines  are  found  in  New  Cale- 
donia, in  the  South  Pacific,  where  they  have  been  mined  for 
some  5^ears  past,  and  have  furnished  in  the  last  decade  the 
largest  part  of  the  world's  supply.     The  ores  occur,  as  is  the 

'  F.  W.  Clarke  andJ.  S.  Diller.  "Nickel  Ores  from  Riddles.   Webster 
and  New  Caledonia,"  Amcr.  Jour.  Sci..  iii.,  XXXV.,  is;}.    H.  B.  v.  Foulloii, 
•On  Ki.ldles."  Jalir.  d.  k.  k:  Oeol.  licichmii.stalt.  1S!»2,  224.     Rec. 

-  Clarke  and  Diller,  as  cited  in  piecedinf?  reference.     S.  H.  Emmens, 

"The  Nickel  Depo.sits  of  North  Carolina,"  Eiig.  (Oid  Min.  Jour.,  .Ajiril  30, 

1S!)3,  p.  4T(i.     H.  Wurtz,  'On  the  Occurrence  of   Cobalt   and    Nickel  in 

<ia.-itim  County,  North  Carolina,"  Ainer.  Asuuv.  A<lr.  Sci.,  XII.,  "JJl ;  Anier. 

■lour.  Sci..  ii..  XXVII..  24. 


440 


KEMP'S  ORE  DEPOSITS. 


usual  case,  associated  with  serpentine,  and  along  the  contact 
of  the  serpentine  with  overlying  beds  of  red  clay.' 

2.15.18.  Example  33a.  Mine  la  Motte.  Considerable 
pyrite  occurs  with  the  lead  ores  mentioned  under  Example  23, 
and  is  separated  in  the  ore-dressing  and  treated  by  itself,  as  it 
contains  nickel  and  cobalt.  Such  pyrite  is  most  abundant  at 
Mine  la  Motte,  and  considerable  matte  is  made  and  shipped 
abroad.  Siegenite,  a  variety  of  linnseite,  is  also  found  im- 
pregnating a  bed  of  Cambrian  sandstone  that  underlies  the 
lead-bearing  dolomite.  It  is  not  abundant  enough  to  be  of 
practical  importance." 

2.15.10.  Nickel  ores  have  also  been  reported  from  Salina 
County,  Arkansas.^  Millerite  occurs  in  a  vein  with  quartz 
gangue  in  black  shales.  It  is  not  practically  productive. 
Nickel  is  also  reported  in  a  rather  fine  conglomerate  from 
Logan  County,  Kansas.  It  occurs  with  manganese  and 
limonite  in  the  cementing  material  of  the  rock.*  Oxidized 
nickel  ores  have  also  been  reported  at  the  Lovelock  mines, 
Churchill  Count}',  Nevada,  which  passed  in  depth  into  sul- 
phides.'^ Although  they  were  originally  regarded  as  promising, 
they  have  not  proved  a  productive  source  as  yet.  At  the  Gem 
mine,  Colorado,  sulphide  ores  have  also  been  produced.  Millerite 
occurs  as  an  interesting  mineral  in  many  other  places  (St. 
Louis,  Mo. ;  with  red  hematite  in  Jefferson  Count.y,  New  York, 
etc.),  but  is  only  a  rarity.  Its  interesting  position  at  the  former 
locality,  in  hair-like  tufts  in  the  midst  of  geodes  indicates  that 

'  F.  Benoit,  "  Etvule  sur  les  Mines  de  Nickel  de  la  Xoiivelle  Caledonie." 
Bull,  delas  Suciete  de  I'Ind.  Miiierale,  VI.,  ToS,  1H!I>^.  J.  Garnier,  "  Me- 
moire  sur  les  Gisenients  de  Cobalt,  de  Cliroine  et  de  Fer  a  la  Nouvelle 
Caledonie,"  <Soc.  (^'.s  [iigenieurs  Crr/V.s.,  1HS7.  S.  Heard,  Jr..  "New  Cale- 
donia Nickel  and  Cobalt,"  Eiig.  ami  Min.  .four..  August  11.  ISNH,  [.  103. 
D.  I^evat.  A.'<soc.  Fmii^'dise  pour  lAtlnaic.  tics  Sci..  Paris.  IKST.  L. 
Pelaton,  "Carte  CJeologifjiie  de  la  Nouvelle  Caledonie,"  Genie  civile,  1891. 

'  J.  M.  Neill,  "  Notes  on  the  Treatment  of  Nickel  and  Cobalt  Mattes  at 
Mine  la  Motte,"  Tntm.  Amer.  lust.  Min.  Eng.,  XIII  ,  634.  For  additional 
literature  see  under  2.05.09. 

'  Ark.  Geol.  Survey,  1H88,  Vol.  I.,  pp.  34,  35. 

*  F.  P.  Dewey,  "On  the  Nickel  Ores  of  Russell  Springs,  Logan  County. 
Kansas,"    Trans.    Aiuer.    Inst.    Min.    Eng.,  XVII.,  (i36. 

"  A.  !?.  Ho<lges.  "  Notes  on  the  Occurrence  of  Nickel  and  Cobalt  Ores  in 
Nevada,"  Trans.  Amer.  Inst.  Min.  Eng.,  X.,  TmT.  S.  B.  Newberry,  "Nickel 
Ores  from  Nevada,"  Amer.  Jour.  Sci.,  iii..  XXVIII..  123. 


TUE  LESSER  METALS,   CONTINUED. 


441 


3  contact 

isiderable 
imple  23, 
self,  as  it 
undant  at 
d  shipped 
Eound  im- 
ierlies  the 
b  to  be  of 

•om  Salina 
ith  quartz 
productive, 
erate  from 
anese  and 
'  Oxidized 
ock  mines, 
)th  into  sul- 
i  promising, 

t  the  Gem 
d.  Millerite 

places  (St. 

New  York, 
t  the  former 

dicates  that 

|l(>  Caledonie." 
liirnier,  "iMe- 
l;i  la  Nouvelle 
•New  Cale- 

ris.  1H8T.  L. 
io  civile,  1H»1. 
)l)alt  Mattes  at 
\)r  additional 


^ogan  County. 

ICobalt  Ores  in 
Lerry,  "Nifkel 


nickeliferous  sohitions  must  have  circulated  rather  widely  in 
these  limestones.  In  Jefferson  County  it  probably  resulted 
from  the  decaying  pyritons  mineral  to  which  Smyth  refers  the 
iron  ore,  as  outlined  earlier. 

PLATINUM. 

2.15.5iO.  Some  hundreds  of  ounces  of  platinum  are  annually 
gathered  from  placer  washings  in  northern  California,  and  two 
or  three  times  as  much  more  from  British  Columbia.  Much 
iridium  and  osmium  are  associated  with  it.  In  October,  1889, 
F.  L.  Sperry,  the  chemist  of  the  Canadian  Copper  Company, 
of  Sudbury,  discovered  a  heavy  crystalline  powder  in  the  con- 
centrates of  a  small  gold-quartz  mine  in  the  district  of  Algoma. 
He  detected  the  presence  of  platinum,  and  sent  the  material  to 
Professors  Wells  and  Penfield,  of  Yale,  by  whom  it  was  ana- 
lyzed and  crystallographically  determined  to  be  the  arsenide 
of  platinum,  PtAsg,  the  first  compound  of  platinum,  other  than 
an  allo}^  detected  in  nature.  It  has  been  appropriately  named 
sperrylite  by  Wells,  and  although  not  at  present  a  source  of 
platinum,  it  may  merit  attention,  as  the  price  of  the  metal  has 
sometimes  approximated  that  of  gold.  The  chief  reliance  of  the 
world  for  platinum  is  Russia,  whose  deposits  are  in  the  Urals. 
More  or  less  comes  also  from  Colombia,  South  America,  and 
from  placer  washings  elsewhere.  Serpentine  is  very  generally' 
its  mother-rock.' 


TIN. 

3.15.31.     Ores:  Cassiterite,  SnO,,  Sn.  78.G7,  O.  21.33. 
sulphide  stannite  is  a  rather  rare  mineral. 


The 


'  California:  Etiq.  and  Min.  Jour.,  June  29,  1889,  587.  B.  Silliman, 
"Clieiokee  (iold  \Vashiiif::s,  California,"  Amcr.  Jottr.  Sci.  iii..  XL,  \'S2. 
Canada:  F.  W.  Clarke  and  Ch.  Catlett,  "  Platiniferous  Nickel  Ore  from 
Canada,"  Amcr.  Jour.  <SV/.,  iii.,  XXXVII.,  872.  H.  L.  Wells  and  S.  L. 
I'enHeid.  "Sperrylite,  a  N'^w  Mineral,"  Idem,  iii.,  XXXVII..  B7.  Russia: 
A.  Daubree,  "On  the  PI  itiniferons  Rocks  of  the  Urals,"  Tnnis.  French 
.Vend.  Sci.,  March,  1875  Amer.  Jour.  Sci.,  iii.,  IX.,  470.  Ceneral  pajKir 
by  C.  Bullnian,  The  Mineral  Indiisiry  for  ISSJ,  p.  87:?.     Rec. 

'  An  elaborate  review  of  tlie  tin  mines  of  the  world  by  C.  M.  Roelker 
will  be  found  in  the  A' 17.  Anu.  Rep.  of  the  Director  of  the  U.  S.  Geol. 
Survey,  Part  III.,  pp.  458-538,  1895.  E.  Reyer  has  given  a  general  dis- 
cussion in  "Zinu,  eiue  geologisch-montanistisch  historische  Monographie," 
Berlin,  1881.  A  general,  genetic  discussion  is  given  by  J.  H.  L.  Vogt, 
"Die  Zinnstein  gang-gruppe,"  Zeits.  fi'ir prakt.  Geol.,  1895,  145. 


Ill 


442 


KEMP'S  ORh:  D/iJPOSIjn 


? 


11. 


Caasiterite  occurs  in  small  stringers  and  veins  on  the  borders 
of  granite  knobs  or  bosses,  either  in  the  granite  itself  or  in  the 
adjacent  rocks,  in  such  relations,  that  it  is  do'ibtless  the  result 
of  fumarole  action  consec^uent  on  the  intrusion  of  the  granite. 
It  appears  that  the  tin  oxide  has  probably  been  formed  from 
the  Huoride.  A  favorite  rock  for  the  ore  is  the  so-called 
greisen,  a  mixture  of  (juartz  and  nniscovite  or  lithia  mica,  and 
probably  an  original  granite  altered  by  fumarole  action. 
Topaz,  tourmaline,  and  Huorite  are  found  with  the  cassiterite, 
and  indicate  fluoric  and  boracic  fumaroles.  Wolframite,  schee- 
lite,  zinnwaldite  and  one  or  two  other  minerals  are  character- 
istic associates.  Cassiterite  seems  also  to  crystallize  out  of  a 
granite  magma  with  the  other  component  minerals.     Cassite- 


Fig.  Wi.—ITorizontdl  section  of  the  Etta  f/miiitie  knob.  Black  Hills,  S.  D. 
After  W.  I\  Blake.  Mineral  I'icsoiirces,  1884,  p.  003. 

rite,  being  a  very  heavy  mineral,  accumulates  in  stream 
gravels,  like  placer  gold,  affording  thus  the  stream  tin.  When 
of  concentric  structure  the  ore  is  called  wood  tin.  It  is  not  yet 
demonstrated  that  the  United  States  have  workable  tn  mines. 

2.15.22.  ExampleSl.  Black  Hills.  Cassiterite  disseminated 
in  masses  of  albite  and  mica  and  associated  with  immense 
crystals  of  spodumene,  which  are  contained  in  knobs  of  granitic 
rock.  Columbite,  tantalite,  and  beryl  are  also  found.  There 
are  two  granite  knobs  which  are  best  known,  the  Etta  and  the 
Ingersoll.  The  former  is  a  conical  hill,  which  pierces  mica  and 
garnetiferous  slates  and  which  is  250  feet  high  by  l^^^)  feet  by 
200  feet.     Tunnels  show  it  to  have  a  concentric  structure — first. 


■ 


TUB  LEt^SER   METALS,   CONTINUED. 


448 


a  zone  of  inica;  second,  a  zone  of  great  spniliunene  crystals, 
with  an  albitic,  Ho-called  greiseu  wliich  carries  cassiterite  in 
its  interstices;  lastly,  a  mixture  of  (juartz  and  feldspar  as  a  core. 
Other  tin-bearing  granites  occur  as  dikes,  or  veins,  as  much  as 
80  feet  wide,  and  bearing  the  so-called  greisen  and  tin  ore  in 
quartz.  They  are  called  segregated  veins  by  Carpenter,  who 
doubts  their  true  igneous  character,  probably  on  good  ground. 
No  tin  is  yet  commercially  produced.  The  tin  deposits  extend 
also  into  Wyoming.' 

2.15.'^3.  Pebbles  of  stream  tin  have  been  found  in  gold 
washings  in  Montana  and  Idaho.  Tin  is  also  known  in  the 
Temescal  Moimtains,  southern  California.  The  area  has  re- 
cently been  described  by  H.  W.  Fairbanks,  who  summarizes 
the  geological  relations  as  follows:  "A  semi-circular  area  of 
granite,  over  two  miles  in  diameter,  surrounded  on  the  north- 
west and  south  by  porphyries,  and  joined  on  the  east  to  a  great 
body  of  granitic  rocks  extending  indetinitely  in  that  direch'on. 
Around  the  border  of  this  granite  ])rotuberance  are  many  dikes 
of  a  fine-grained  granite.  Cutting  through  the  granite  in  a 
northeast  and  southwest  direction  are  black  tourmaline  veins, 
which  form  the  gangue  of  the  tin  ore  when  it  is  present." 
While  tourmaline  is  a  common  associate  of  tin  ores,  this  great 
abundance  of  it  is  unusual.  The  ore  occiu-s  as  a  yellow,  un- 
orystalline  variety,  in  layers,  and  as  a  brown,  granular,  mas- 
sive form,  or  in  brown  crystals.  The  ore  and  veinstone  seem 
to  have  replaced  th^  usual  minerals  of  the  granite,  doubtless  b}' 
fumarole  action  along  fissures.  The  mining  proved  unsuccess- 
ful after  a  serious  attempt.^ 

^'Wrv7m-Ak^,   Mineral  ^^^R^^^^  1SS;?-H4.  p.  m-i.     Kec.     Anwr.  ,/oin: 

Sci..  September,  1883,  p.  '-iir);  E)i(j.  (iiid  Mill.  Jam:.  Sei)teml)pr  S,  t8S(i. 
"Tin  Ore  Deposits  of  tlie  Blaek  Hills,"  Trans.  Amer.  Inst.  Min.  Eng., 
XIII..  (>!>1.  F.  K.  Cariienter,  Prdiin.  Rep.  Dak.  School  of  Mine.'i."  1888; 
also  Tran.'i.  Amer.  Inst.  Min.  Entj.,  XVII.,  oTO.  -'Tin  in  tiie  Black  Hills," 
Eiaj.  and  Min.  Jour..  November  28,  1884,  ji.  ;}.')!{.  Mineral  Re.'<oiirce.s  of 
tlie  U.  S.,  anmially  uiuler  "Tin."  W,  P.  Headden,  "Notes  on  the  Dis- 
covery anil  Occurrence  of  Tin  Ore  in  the  liJack  Hills,"  Colo.  Sei .  Soc., 
HI,,  ;U7,  A.  .1.  .Morse,  ■  Harney  Peak  Tin  ;\Iines."  Eny.  and  Min.  Jour., 
November  17,  1H1»4,  p.  4«;?. 

'^  W.  P.  Blake,  '  Occurrence  of  Wood  Tin  in  ralifornia,  Idaho,  and  Mon- 
tana," J//».  and  Sci.  Press.  San  Francisco,  August"),  188:2.  H.  \V,  Fair- 
hanks,  "The  Temescal  Tin  District."  ^/e?VHY/t  Rep.  Cal.  State  Mineral- 
ogist. ISO;},  pp.  111-114.  .\  fuller  paj^er  will  he  found  inthe.h^cr.  Jour. 
Sei.,  July,  1897, :{!».    II.  CJ,  Hanks,  Rep.  Cal.  State  Mineralogist,  1884,  p.  131. 


:  ■;  I 


444 


KEMP'S  ORE  DEPOSITS. 


3.15.34.  Narrow  veins  carry iug  casaiterite  have  been  ex- 
ploited in  the  granite  and  schistose  rocks  of  Rockbridge  and 
Nelson  counties,  Virginia,  in  North  Carolina,  and  in  Alabama. 
Companies  have  been  formed  to  work  the  two  former,  but  as 
3'et  without  a  notable  output.' 

3.1.5.25.  Cassiterite  has  been  discovered  in  narrow  veins  in 
mica  schists  with  lepidolite  and  fluorite  at  Winslow,  Me.,  and 
is  known  at  other  places  in  Maine  and  New  Hampshire.  A 
salted  tin  prospect  several  years  ago  spread  the  impression  that 
tin  was  to  be  found  in  Missouri.^ 

Narrow  quartz  veins  have  been  recently  discovered  near  El 
Paso,  Tex.,  with  cassiterite  richly  disseminated  through  them. 

3.15,30.  Mexico.  Tin  ores  occur  in  a  great  number  of 
places  in  Mexico,  and  small  amounts  of  tin  have  been  pro- 
duced during  and  since  the  time  of  the  Aztecs.  W.  R.  Ingalls 
has  carefully  described  the  deposits  in  the  State  of  Durango. 
and  has  shown  that  those  at  Potrillos  are  in  veinlets  or  small 
veins  in  rhyolitic  tuffs,  with  associated  topaz,  chalcedony  and 
hyalite.  The  cassiterite  is  in  irregular  bunches  and  nodules, 
but  as  in  practically  all  the  Mexican  mines,  the  amount  is  too 
small  to  be  the  basis  of  extended  mining.  Alluvial  gravels 
were  earlier  worked  but  have  been  long  since  exhausted.  At 
Cacaria,  likewise  in  Durango,  the  wall  rock  is  described  as 
quartz- porphyry,  but  near  the  city  of  Durango,  and  at  Sain 
Alto,  Zacatecas,  the  rhyolite  tuffs  are  again  the  country  rock.' 
The  tin  of  Durango  runs  high  in  antimony. 


'  H.  D.  Campbell,  "  Tin  Ore.  Cassiterite,  in  the  Blue  Eidpje  in  Virginia," 
The  Virginia^,  October,  IS8I?.  A.  R.  Ledoux,  "Tin  in  North  Carolina.  ' 
Eug.  and  Mi n.  Jour.,  December  14,  1889,  p.  521;  see  also  February,  1887, 
p.  111.  MfCreath  and  Piatt,  Bull.  Iron  and  Steel  A.hsoc,  November?, 
188;{,  p.  'M).  W.  Robertson,  London  Min.  Joitr..  October  is,  1884.  A. 
Winslow,  "Tin  Ore  in  Virginia,"  .Bngr.  and  Min.  Jour.,  November,  188."), 
Rec. 

''  W.  P.  Blake,  Mineral  Renourcen,  1884,  p.  538.  C.  H.  Hitchcock, 
"Discovery  of  Tin  Ore  and  Emery  at  Winslow,  Me.,"  Eng.  and  Min. 
Jour..  Octobers,  ISSO,  p.  218.  T.  S.  Hunt,  "Remarks  on  the  Occurrence 
of  Tin  Ore  at  Winslow,  Me.,"  Trana.  Avter.  Inst.  Min.  Eng.,  I.,  578.  C.  T. 
Jack.sou,  "Tin  Ore  at  Winslow.  Me.,"  Proc.  Bo.st.  Soc.  Nat.  Hi.'it.,  XII.,  20)7. 

»  F.  A.  Genth,  "On  the  Cactxria  Ores,"  Proc.  Amer.  Philo.  Soc.  XXIV., 
1887,  p.  23.     W.  R.  Ingalls.  "The  Tin  Deposits  of  Durango,"  Trans.  Amer. 
Innt.  Min.  Eng.,  XXV.,  146.     C.  W.  Kempton,  "Note  on  Tin  Ores  at  Sain 
Alto,  Zacatecas,"  Idem,  997. 


CHAPTER  XVI. 


CONCLUDING   REMARKS. 


2.16.01.  In  review  of  the  western  border  of  the  country,  we 
note  the  elevated  plateau  rising  froio  the  Mississippi  to  the 
Rocky  Mountain  system,  which  consists  of  various  ranges  of 
general  north  and  south  or  northwest  and  southeast  trend,  with 
broad  valleys  between.  To  the  west  the  Colorado  Plateau  is 
met,  and  then  the  Wasatch  Mountains  and  the  Great  Basin,  with 
its  various,  subordinate,  north  and  south  ranges.  These  are 
succeeded  by  the  Sierra  Nevada,  and  the  great  valley  of  Cali- 
fornia, the  Coast  range,  and  finally  the  Pacific  Ocean. 

From  the  Archean  to  the  close  of  the  Carboniferous  thei'e 
were  granitic  islands  around  which  active  sedimentation  pro- 
ceeded. At  the  close  of  the  Carboniferous  the  elevation  of  the 
Wasatch  and  the  region  of  eastern  Nevada  occurred.  At  the 
close  of  the  Jurassic  the  elevation  of  the  Sierra  Nevada  took 
place.  Tlie  chief  upheaval  of  the  Rocky  Mountain  system 
came  at  the  close  of  the  Cretaceous  and  that  of  '  .e  Coast  range 
at  the  close  of  the  Miocene  Tertiary.  Smaller  and  less  impor- 
tant oscillations  have  occurred  before  and  since.  Each  eleva- 
tion was  accompanied  by  foldings,  faultings,  and  extensive 
outpourings  of  eruptive  rocks.  The  resultant  fractures  and 
the  circulation  of  hot  and  chemically  active  solutions,  occasioned 
by  the  dying  volcanic  activity,  constitute  the  primary  cause  of 
the  formation  of  the  ore  deposits,  which  in  some  cases  lie  in 
ranges  along  tlie  lines  of  faulting  or  of  disturbances,  and  in 
others  are  irregularly  scattered.  We  may  recognize  the  Coast 
range  belt  with  mercury  and  chromium;  the  California  gold 
belt  in  the  western  Sierras;  the  silver  belt  of  Utah  on  the  west- 
ern flank  of  the  Wasatch;  a  belt  in  Arizona  from  southeast  to 
northwest,    along  the    contact   between    Paleozoic    limestone, 


440 


KKMP'8  ORE  DEPOSITS. 


mostly  Carbouiferous,  antl  the  Archoan;  and  the  great  stiMoh 
of  lead-silver  mines  in  the  Carbouiferous  limestones  of  Colo- 
rado. The  other  areas  are  scattered,  and  apparently  exhibit 
no  such  grand  general  relations  to  these  geographical  and  geo- 
logical phenomena.' 

'2.1().02.  In  the  Mississippi  Valley,  W.  P.  Jenney  has  re- 
marked the  connection  of  the  antimony  and  silver  deposits  of 
Arkansas  with  the  Ouachita  uplift  that  traverses  that  State 
and  Indian  Territory;  the  location  of  the  Missouri  lead  and 
zinc  ores  along  the  Ozark  uplift;  and  he  hfis  referred  the 
Wisconsin  lead  and  zinc  mine&,  as  well  as  those  in  the  neigh- 
boring parts  of  Iowa 'and  Illinois,  to  an  uplift  south  of  the 
Archean  area  of  Wisconsin.  The  limitation  of  the  Lake 
Superior  copper  deposits  to  the  Keweenawan  system  maj'  be 
mentioned,  and  such  parallelism  as  prevails  among  the  Lake 
Superior  iron  ores.  In  the  East  the  great  belt  of  Clinton  ores; 
the  long  succession  of  Siluro-Cambrian  limonites  in  the  Great 
Valley;  the  black-band  ores  and  clay-ironstones  of  the  Carbon- 
iferous; the  closely  similar  geological  relations  of  non-titanifer- 
ous,  magnetite  lenses  in  the  Archean  gneisses;  and  the  general 
association  of  titan iferous  magnetites  with  rocks  of  the  gabbro 
family  the  country  over — all  are  striking  illustrations  of  broad, 
general  geological  features  that  may  cbaracterire  extended 
series  of  ore  deposits.  To  these  may  be  api)ended  the  great 
series  of  pyritous  veins  in  the  slates  and  schists  of  the  East,  the 
gold  belt  of  the  Southeastern  States,  and  the  small  copper  de- 
posits associated  with  the  Triassic  traps  and  sandstones.  Aside 
from  the  groups  mentioned,  while  there  are  important  mines 
not  included  in  the  list,  the  others  do  not  exhibit  the  same  wide- 
spread uniformities  of  structure  or  associations.^     Yet,  from  the 


'  G.  F.  Becker,  Amer.  Jour.  Scl,  Third  Series,  Vol.  XXIII.,  1884,  p. 
209,  W.  P.  Blake,  Rep.  Cal.  State  Board  of  A(jrienlture,  IHdfi.  S.  F. 
Emmons.  "  The  Structural  Relations  of  Ore  Depo.sits,"  Trans.  Amer.  Inst. 
Min.  Eng.,  XVI.,  804.  R.  W.  Raymond,  "Geographical  Distribution  of 
Mining  Districts  in  the  United  States,"  Idem,  I.,  'X\.  Fortieth  Paralhl 
Survei/,  Vol.  III.,  Chapter  I.     "  Precious  Metals,"  Tenth  Census,  Vol.  XI 1. 

'  It  is  only  proper  in  this  connection  to  refer  to  the  ])ai)er  by  T.  F.  Van 
Wagenen,  on  "System  in  the  Location  of  Mining  Districts."  School  of 
Mines  Quarterlji.  .January,  1808.  p.  189.  The  autiior  regards  the  location 
of  the  veins  and  the  mining  di.stricts  as  having  been  determined  by  the 
lines  of  terrestrial,  magnetic  currents,  whicii  converge  at  the  magnetic 


co^CL  UDiya  it  km.  i  n  ks. 


447 


t  strtich 

I  of  Colo- 

j  exhibit 

and  geo- 

)y  has  re- 
epos  its  of 
that  State 
lead   and 
'erred  tlie 
he  ueigh- 
ith  of  the 
the   Lake 
n  may  he 
r  the  Lake 
inton  ores; 

the  Great 
he  Carhon- 
a-titauifer- 
:he  general 
the  jj;ahl)n) 
IS  of  broad, 
extended 

the  great 
,e  East,  tlie 
[Copper  de- 
les. Apide 
ftant  mines 

same  wide- 

;,  from  tht 

[II..  1884,  p. 

18(U5.     B.  F. 

Amer.  In  ft. 
htiibiition  of 
i'th  PaniUcl 
Ls,  Vol.  XTl. 
\)y  T.  F.  Van 
Js,"  Scltool  of 

the  location 
Itiined  by  tho 
Ihe  magnetic 


list  cited,  it  forcibly  appears  that  similar  conditions  have 
brought  about  related  ore  bodies  over  great  stretches  of  country ; 
and  while  in  the  opening  schemes  of  classification  points  of 
difference  were  emphasized,  in  the  closing  pages  points  of  re- 
semblance may  he  with  eipial  right  brought  to  the  foreground. 

2.10.03.  A  few  general  conclusions  suggest  themseiv&a  from 
the  preceding  pages. 

(1)  The  extreme  irregularity  in  the  shape  of  metalliferous 
deposits,  and  from  this  the  unwisdom  of  the  United  States  law 
in  the  West,  which  is  based  on  well-defined  fissure  veins. 
The  only  practicable  method  is  that  a  man  should  own  all  that 
is  embraced  in  his  property  lines,  whether  the  ore  body  out- 
crops outside  or  not.  "A  square  location  is  the  square  thing" 
(Raymond). 

{'l)  The  very  general  proximity  of  eruptive  rocks  in  some 
form  to  the  ore  bodies.  Except  in  the  case  of  iron,  there  are 
only  a  few  where  these  are  not  present,  and  apparently  strong 
factors  in  the  circulations  which  formed  the  ore.  The  lead  and 
zinc  deposits  of  eastern  and  western  Missouri  and  the  neighbor- 
ing States,  and  of  New  York  and  Virginia,  are  almost  the  only 
ones,  and  we  are  justified  in  concluding  that  eruptive  rocks  are 
of  great  importance. 

(;>)  We  know  from  the  investigations  of  Sandberger  and 
others  that  the  dark  silicates  of  manj'  rocks  contain  percentages 
of  the  common  metals.  The  choice  is  open  whether  to  refer  the 
ore  to  original  disseminations  in  these,  and  to  derive  it  by 
gradual  concentration,  probably  at  great  depths,  or  to  some 
indefinite  unknown  source,  which  can  only  be  described  as 
"below." 

IK)le  of  the  earth.  Tliey  therefore  are  indejiendent  of  the  ^reat  lines  of 
nionntain  makin<?  and  igneous  outbreaks.  Tlie  l.-itter  are,  however,  re- 
ga riled  by  the  present  writer  as  of  paramount  importance;  See  above 
ixiragraph. 


r      f  I » \*t 


APPENDIX   I. 

In  the  following  pages  the  principal  schemes  of  classification 
of  ore  deposits  are  grouped  according  to  certain  relationships 
and  similarities  that  run  through  them.  It  would  be  interest- 
ing to  arrange  them  in  chronological  order,  but  points  of  like- 
ness and  uulikeness  would  not  thus  be  brought  out,  nor  can  the 
influence  of  one  writer  on  another  be  so  clearly  emphasized. 
The  underlying  object,  aside  from  showing  in  a  bird's-eye  view 
what  has  been  done,  is  to  lead  up  to  the  purely  genetic  class- 
ification which  appears  in  Chapter  YI,  Part  I.,  and  which 
would  properly  come  in  after  No.  1(5.  In  the  earlier  editiona 
of  the  book  it  was  so  placed,  and  all  the  schemes  formed  part 
of  Chapter  VI,  but  so  many  have  appeared  in  later  years  that 
it  has  seemed  wiser  not  to  overload  the  main  text  with  matter 
that  is  largely  a  subject  of  reference,  and  that  can  be  treated 
with  greater  freedom  in  an  appendix.  The  importance  of  the 
genetic  principle  has  been  more  and  more  appreciated  in  recent 
years,  and  it  is  a  striking  fact  that  the  more  weighty  recent 
contributions  on  ore  deposits  have  been  dominated  by  it. 

In  reading  this  appendix  it  should  be  further  appreciated  that 
the  schemes  were  originally  grouped  so  as  to  lead  up  to  the  one 
on  page  od  as  a  climax,  and  that  in  it  mere  form  is  eliminated  to 
the  last  degree,  and  weli-recoguized  geological  phenomena  are 
brought  to  the  foreground.  It  has  indeed  been  s^aid  with  force 
that  the  origin  of  ore  deposits  is  a  subject  which  is  very  largely 
a  matter  of  hypothesis,  and  that  it  involves  profound  subter- 
ranean causes,  of  which  we  know  but  little.  Still,  it  is  held 
that  an  acquaintance  with  what  has  been  accomplished  in  re- 
cent years  by  our  best  workers,  and  a  rigid  adherence  to  well- 
recognized  principles  in  geology  and  mineralogy,  especially  as 
developed  in  rock  study  {i.e.,  in  that  department  of  geology 
that   of  late  years  we  have  grown    to    call  petrology),    will 


^ 


APPENDIX  L 


449 


establish  much  that  cannot  be  (luestioned,  and  will  aid  in 
differentiating  the  cases  which  are  still  objects  of  reasonable 
doubt.  It  is,  however,  true  that  among  the  sul)jects  on  which 
human  imagination,  often  superstitious,  has  run  to  wild  ex- 
tremes, and  on  wliich  cranky  dreamers  have  exercised  their 
wits,  the  origin  of  ore  deposits  stands  out  in  particularly  strong 
relief. 

A.  Schemes  Inuolviug  onlij  the  Classification  of  Veins. 


(I) 

G.  A.  von  Weissenbach/     Gamjstudien,  1850,  p.  12. 

(a)  Sedinieutiirgiinge  (Sedimentary  Veins). 

(b)  Kontritionsgiluge  (Attrition  Veins). 

(f)  Stalactitische   oder  Intiltrationsgiinge    (Stalactitie   or 
Infiltration  Veins). 

(d)  Plutonische  oder  Gebirgsmassengiinge  (Masses,  dikes, 

knobs,  bosses,  etc.,  not  necessarily  with  ores). 

(e)  Ausscheidungsgange  (Segregated  Veins). 

(f)  Erzgange  (True  or  Fissure  Veins). 

(2) 

B.  von  Cotta,  in  comments  on  Von  Weissenbach's  Scheme. 
Gangstiidien,  1850,  p.  79.  According  to  the  vein 
filling. 

1.  Gesteinsgange  (Dikes). 

{a)  Not  crystalline  (Sandstone). 
(b)  Crystalline  (Granite). 

2.  Mineralgange  (Veins). 

(a)  Of  one  non-metallic  mineral. 

(b)  Of  several  non-metallic  minerals. 

3.  Erzgange.     Ore  veins. 

(3) 

B.  von  Cotta,  Idem,  p.  80,    According  to  Shape  and  Position. 
I.  Wahre,  einfache  Spaltengange  (Fissures). 

(a)  Querdurcbsetzende  (Cross  fissures). 

(b)  Lagergiiuge  (Bed  veins). 

(c)  Kliifte  (Cracks),  Adern  (Veinlets). 


»  See  also  Whitney's  Metallic  Wealth  of  the  U.  S.,  1854,  p.  44. 


':,  ■  m 


i' 


450  KHMP's  oiiK  DKvossna. 

II.  Qangzii^o  (Linked  Veins).' 

III.  Not/,giiuj:e  (Keticuhited  Veiun). 

IV.  Coutaktgilnge  (Contact  VeiuB). 
V.  Lenticularg}luge  (LeuHes). 

VI.  Stock  form  i  go  Gslngo  (Stocka,  Masses). 

(4) 

B.  von  Cotta,  Idem,  p.  80.     According  to  tbe  texture  of  f 
vein  tilling. 
I.  Dichte  (iiingo  (Compact  Veins). 
II.  Krystalliuinche  Gjinge. 

III.  KryHtalliniHcli,  kornige  (granular)  flange. 

IV.  Krystallinisch,  massige  (massive)  Giinge. 
V.  Gilnge  mit  Lagentextur  (Banded  veins). 

(a)  Ohne  Synnnetrie  der  Lagen  (unsymmetrical). 
[h)  Mifc  Symmetrie  der  Lagen  (Hj-nnnetrioal). 
VI,  Gauge  mit  Breccieu  oder  Conglomerattextur. 

(6) 

J.  Le  Conte,  Anier.  Jour.  Sci.,  July,  188;},  p.  17. 

1.  Fissure  Veins. 

2.  Incipient  Fissures,  or  Irregular  Veins. 

3.  Brecciated  Veins. 

4.  Substitution  Veins. 

5.  Contact  Veins. 

6.  Irregular  Ore  Deposits. 

In  von  Weissenbach's  table  the  sedimentary  veins  are 
much  the  same  as  the  "sandstones  dikes"  which  J.  S. 
Diller  has  recently  described.  {Hull.  (ieol.  Soc.  Anier.,  I., 
411.)  They  and  the  stalactitic  veins  have  small  practical 
value,  although  of  great  scientific  interest.  Under  {d),  the 
stockworks  with  tin  ores  are  the  principal  illustration  of  eco- 
r^omic  prominence.  The  attrition  veins  are  an  important  class, 
and  increasing  study  has  widened  the  application  of  this  or 


'  GauRziige  is  liap])ily  translated  "linked  veins,"  by  Dr.  G.  F.  Becker 
(Qitickniln'r  Di'posits.  p.  410).  Any  attempt  to  render  the  orij:;inal  by 
preserving  the  tigure  of  a  tlock  of  birds  or  of  a  school  of  lish,  etc.,  is,  as 
Mr.  Becker  remarks,  infelicitous,  if  not  inipo.ssible. 


API'KAniX  I. 


451 


synonymous  terms.  Segregnted  veins  antl  true  veins  are  well- 
known  forms.  In  the  comments  of  von  Cotta,  which  follow 
von  Weissenbaoh's  paper,  veins  are  grouped  from  every  possi- 
ble standpoint,  von  WeiyHenbacirn  sclienie  beiny:  taken  as  the 
one  based  on  origin.  Nos.  'Z  and  4  have  small  claims  to  atten- 
tion. No.  .'{  foreshadows  the  drift  of  many  subseipjent  writers. 
The  meanings  of  the  terms  are  self-evident,  except  perhaps 
Gangziige  (linked  veins).  This  refers  to  a  group  of  parallel  and 
more  or  less  overlapping  veins,  deposited  along  a  series  of 
opening,  evidently  of  common  origin.  It  is  a  convenient  term. 
The  terms  used  by  LeConte  may  bo  passed  without  comment 
as  bemg  self-evident  in  their  meaning,  except  (4)  and  ((1).  The 
scheme  was  devised,  as  a  perusal  of  the  citation  will  show, 
after  the  author  had  set  forth  some  original  views  of  the  causes 
which  lead  to  the  precipitation  of  ores,  and  had  forcibly  stated 
others  very  generally  accepted.  In  the  explanatory  text  some 
({uite  curious  associations  are  found,  which  are  cited  by  way  of 
illustration.  Thus,  under  group  (4),  stalactites,  caves,  gash 
veins,  and  the  Ltjadville  ore  bodies  are  considered  examples, 
and  under  group  (O)  the  grouping  together  of  beds,  igneous 
masses,  and  all  other  forms  of  so-called  irregular  deposit  is 
decidedly  open  to  criticism.  This  is  the  more  emjjhatic  be- 
.'!ause  the  concluding  sentences  of  the  naper  (of  whose  general 
value  and  excellence  there  can  be  no  qu.  4ion)  givo  the  impres- 
sion that  the  author  felt  he  had  cleared  .  all  the  points  in  the 
origin  of  ore  bodies  which  would  be  of  interest  or  importance 
to  a  purely  s(uentific  investigator  as  contrasted  with  a  practical 
miner. 

B.   General  Schemes  Based  on  Form. 


(6) 

Von  Cotta  and  Prime.     Ore  Deposits,  New  York,  1870. 
I.  Regular  Deposits. 

A.  Beds. 

B.  Veins. 

(a)  True  (Fissure)  Veins. 
(6)  Bedded  Veins. 

(c)  Contact  Veins. 

(d)  Lenticular  Veins. 


'flHl 


•III 


Mm] 


ll'- 


462  KEMP'S  ORE  DEPOSITS. 

II.  Irregular  Deposits. 

C.  Segregations. 

(a)  Recumbent. 

(b)  Vertical 

D.  Impregnations  (Disseminations), 

(V) 
Lottner-Serlo,  Leitfaden  zur  Bergbaukunde,  1869. 
I.  Eingelagerte  Lagerstiltten  (Inclosed  Deposits). 

A.  Plattenformige  (Tabular). 

(a)  Giinge  (Veins). 

(&)  Flotze  und  Lager  (Strata,  beds,  seams). 

B.  Massige  Lagerstatten  (Massive  Deposits.) 

(a)  Stocke  i  Ma^^p^ 

(b)  Stockwerke  f  ^^^^sses. 

C.  Andere  unregelmassige  Lagerstatten  (other  ir- 

regular deposits). 

(a)  Nester  (Pockets). 

(b)  Putzen. 

(c)  Nieren  (Kidneys). 

II.  Aufgelagerte  Lagerstatten  (Superficial  Deposits). 

D.  Triimmerlagerstatten  (Placers). 

E.  Oberllachliche  Lager  (Surface  beds). 

(8) 
Koebler,  Lehrbuch  der  Bergbaukunde,  1887. 

I.  Plattenformige  Lagerstatten  (Tabular  Deposits), 
(a)  Giinge  (Veins). 

(6)  Flotze  und  Lager  (Strata,  beds,  seams). 
II.  Lagerstatten  von  unregelmassige  Form  (Deposits  of 
irregular  Form), 
(a)  St<)cke  und  Stockwerke  (Masses). 
ib)  Butzen,  Nester,  und  Nieren  (Pockets,  concre- 
tions, etc.). 

(^) 
Gallon,  Lectures  on  Mining,  188G   (Foster  and  GallowayV 
translation). 
I.  Veins. 
II.  Beds. 
III.  Masses  {i.e.,  not  relatively  long,  broad,  and  thin). 


[869. 
Dosits). 


eds,  seams). 
Bposits.) 


ten  (other  ir- 


deposits). 

8). 

'eposits). 

3ams). 
(Deposits  of 

kets,  concre- 
I  Galloway's 

md  thin). 


APPENDIX  I. 
of  ""te^r^ite  7"  ""T  "f  ''"■'"«  •'^™-  »'  'he  principle 

are  from  treatises  on  minine   in  wh.Vh  *i  f-  *'"'™ 

-inor  r6,e,  and  indicates  Z  iX^t  LTd  Cab'^r  ^ 
m.nmg  engineers,  wlien  writing  theoret  ca^v  To  i  ' 

ta.n  fairly  deHnite  forms,  which  «"«  ^ploited  1'™  "'" 
ouriy  remarked,  however,  considering  the  nncertaintt  o^"' 
bodies  and  their  variability  in  sliam  iti!i  "'■'"'"*'""'y  of  ore 

^  as  for  e.ampi.  Stock,  Bnt  J  (plnKeri"! 

C.  &Aem.s,  Pa,-«i,  Based  on  Form,  Partly  o„  Origin. 

(10) 


I 
II 


Superficial. 
Stratified. 

(«)  Con^^tituting  the  mass  of  a  bed  or  stratified  de- 

{b)  Disseminated  through  sedimentary  beds 

ic)  Orjg.nally   deposited   fr<.„    aqueous  sltion 

III.  Unstratifier""^"^*^"^^^^^^^^^- 
A.  Irregular. 

{(t)  Masses  of  eruptive  origin 
-       {!>)  Disseminated  in  eruptive  rocks, 
(c)  btockwork  deposits. 
{d)  Contact  deposits. 
(«)  Fahl bands. 
B.  Regular. 

(/)  Segregated  veins. 

{<j)  Gash  veins. 

{h)  True  or  fissure  veins. 


154 


KEMP'S  ORE  DEPOSITS. 


(11) 


'.<tt#. 


.-.  i; 


J.  S.  Newberry,  School  of  Mines  Quarterly,  March,   1880, 
May,  1880. 
I.  Superficial. 
II.  Stratified. 

(a)  Forming  entire  strata. 

(b)  Disseminated  through  strata. 

(c)  Segregated  from  strata. 
III.  Unstratified. 

(a)  Eruptive  masses. 

(b)  Disseminated  through  eruptive  rock. 

(c)  Contact  deposits. 

(d)  Stockworks. 

(e)  Fab  1  bands. 
(/)  Chambers. 
(g)  Mineral  veins. 

1.  Gash  veins. 

2.  Segregated  veins. 

3.  Bedded  veins. 

4.  Fissure  veins. 

(12) 

J.  A.  Phillips,  Ore  Deposits,  1884. 
I.  Superficial. 

(a)  By  mechanical  action  of  water. 
(6)  By  chemical  action. 
II.  Stratified, 

(«)  Deposits  constituting  the  bulk  of  metalliferous 
beds  formed  by  precipitation  from  aqueous 
solution. 
(6)  Beds  originally  deposited  from  solution  but 

subscMjuently  altered  by  metamorphism. 
(c)  Ore  disseminated  through  sedimentary  beds,  in 
which  they  have  been  chemically  deposited. 
III.  Unstratified. 

(a)  True  veins. 

(b)  Segregated  veins. 

(c)  Gash  veins. 

(d)  Impregnations. 

(e)  Stockworks. 


^arch,  1880, 


)ck. 


metalliferous 
from  aqueous 

solution  but 
tiorphism. 
jntary  beds,  in 
illy  deposited. 


(/)  Fahlbands. 

(9')  Contact  deposits. 

(/')  Chambers  or  pockets. 


455 


fteatio„8.  Newberry  i.Ci„ri  ^-  "'  """■"''  '^"8"  """"i- 
«nd  bedded  veins..  TbeH  "  ,,  „I  ''''''*'''''''''™'  """""bers, 
.t  is  not  always  easy  to  dis fe^uth  '"  "  ""•""'  'o™'  '""■ough 
earlier  giveu.  Th^-s,  they^f He  '"'P'-'^"""""'  from  others 
semiMte,!  tbrough  s  rata    ™.^        ^'^'^i' '''''' the  divisior,,  rffe. 

Hlscsedto  indicate  places  alol/""?'     ^I^"  '™^<i  '■« 

sprea,l  into  the  walls.     TlTetetm 'I,       ■?   "'""■<'  *•=«  ore  has 
found  app,i,,t,.„^  j^^«te'«    fibers,"  or  "caves,"  has 

BecWed    veins   appear   .lJ-^\':^   ''J  "ff"'    -"ition. 
Phillips  seeks  to  explain  tha        ti    ?  **    ''''o™    (No.   c) 

VVl..t„ey^,sche„,eat  leaHvfeeLlr  "'  ""«- »  ^B  n.,e  ot 
sizing  the  genetic  principle  „L^.  ™Portanee  of  empha- 
plied  in  the  simpler  phraseo  „T.  ™'"^-  *'"«''  «'  i'  i^  *">- 
sentences  lack  the  incis  ^nes^^^^f  tr'"!-*"''  *''^  ''^*«'^'5«'l 
arrangement  as  set  forth  by  wlitne  •""'''f  ^'"'<'"<'«-  The 
and  the  scheme  is  one  of  the  manv  I  i  T""'  °'  ''''s''  P-^ai^e, 
hat  has  playe<l  a  large  Irt  TntL  •*'"'■=«'  i"  «  l>oofc 

United  States.  ^  ""*  economic  history  of  the 

D.  M«m..  Largely  Based  on  Origin. 

(i;)) 

J.  Grimm,  Lagerstfltten,  mm 

■  ^^f^^K'heile  oder  grSssere  Einschlflsse  in  de     n 
birgsgesteinen      ff,n^™.„        ""'*''«  m  den  Ge- 

(Esaentialco^-pontTrnSt""''?*""''"- 
country  „,,    ''i,,,,4~   "'i  -lusionsin 

(o)  Ursprungliche  Einsprenguus      ^Ori   ■     ,      ■  , 
the  inclosing  rock  )  '^'     <<^"g"''al  with 

'-'^  ""thetr  ''rC"'^''  r««e«ibrteBr„ch. 

t.ince     Sacir!  o^h       '^^^^  ''""^  «  '''•«■ 
cias.)  ''™' "'<^''«='""K  boulders.    Brec- 


r  ^:  'I 


456  KEMP'S  ORE  DEPOSITS. 

II.  Untergeordnete  Gebirgsglieder  oder  besondere  Lager- 
statten.      (Subordinate  terranes  or  special  forms 
of  Deposits.) 
(a)     Flatten tVh'mige  Massen.     (Tabular  masses.) 

1.  Lager  oder  Flotze.     Bodensatzbildung. 

(Beds,  strata.) 

2.  Gauge,      Kltifte,     Gangtrummer,     etc. 

(Veins  of  varying  sizes.) 

3.  Plattenformige  Erz-ausscheidungen  ii    1 

Anhilufungen,     (Segregated  veins.) 
(6)  Stocke  und  regollos  gestaltete  Massen.    (Stocks 
and  irregular  masses.) 

1.  Lagerstocke  Linsenst()cke,Linsen.   (Len- 

ticular deposits,  etc.) 

2.  Stocke,  Butzen,  Nester,  etc.      (Masses, 

pockets,  etc.) 

3.  Stockwerke.     (Stock works.) 

(14) 

A.  von  Groddeck,  Lehre  von  den  Lagersintten  der  Erze., 
isri),  p.  84, 
I.  Urspriiugliche  Lagerstatten  (Primary  deposits). 

A.  Gleichzeitig  mit  dem   Nebengestein    gebildet. 

(Formed  at  the  same  time  with  the  walls.) 

1.  Geschichtete.     (Stratified.) 

(a)  Derbe  Erzfiotze.   (Entire  beds  in  a  stratified 

series. ) 

(b)  Ausscheiduugsflotze.        (Disseminated      in 

beds. ) 

(c)  Erzlager.     (Lenticular     beds,     mostly     in 

schists. ) 

2.  Massige.     (Massive;  the  word  is  nearly 

synonymous  with  igneous.) 

B.  Spater  wie  das  Nebengestein  gebildet.   (Formed 

later  than  the  walls.) 
3.   Hohlraumsfiillungen.     (Cavity  fillings.) 
(a)  SpaltenfiiUungen  oder  Giinge.    (Fissure  fill- 
ings or  veins.) 
(1)  In    massigen   Gesteinen.       (In    igneous 
rocks.) 


[lere  Lager- 
)ecial  forms 

V  masses.) 
satzbildung. 

mmer,     etc. 

[dun  gen  i      ^ 
,te(l  veins.) 
len.     (Stocks 

insen.  (Len- 

c.      (Masses, 


APPENDIX  I. 


467 


n  der  Erze., 

iposits). 

ein    gebildet. 

ith  the  walls. ) 

in  a  stratified 

aminated      in 

1,     mostly     in 

ord   is  nearly 

IS.) 

Idet.   (Forniea 

avity  fillings.) 
.    (Fissure  lill- 

(In    igneous 


-     (2)  In  geschichteten  Gesteinen.     (In  strati- 
fied rocks), 
(6)  Hohlenfiillungen.     (Chambers.) 

4.  Metamorphische  Lagerstatten.    (Altera- 
tions,  replacements,  etc.) 
II.  Truramer-Iagerstatten.     (Secondary    or    detrital  de- 
posits.) 

(15) 
R.  Pumpelly,  Johnson's  Encyclopcedia,  1886,  VI.    22 
I.  Disseminated  concentra- ^  '        ' 


[ 


Forms  due  to  the  text- 
ure of  the  inclosing 
rock,  or  to  its  mineral 
constitution,  or  to 
both  causes. 


III. 

IV. 

V. 

VI. 


J 

j  Forms   chiefly  due    to 
^     pre-existing  open  cav- 
J      ities  or  fissures. 


tion. 
(«)  Impregnations,  Fahl 
bands. 
II.  Aggregated  Concentration, 
(rt)  Lenticular    aggrega- 
tions and  beds. 

(b)  Irregular  masses. 

(c)  Reticulated  veins. 

(d)  Contact  deposits. 
Cave  deposits. 
Gash  veins. 
Fissure  veins. 
Surface  deposits. 

(a)  Residuary  deposits. 

(b)  Stream  deposits. 

(c)  Lake  or  bog  deposits. 

These  three  are  all  excellent,  and  give  some  interesting 
variations   in     he  several   points   of   view   from   which  eTch 
writer  regarded  his  subject.     There  are  instances  in  the  two 
German  schen.es  where  it  is  diflficult  to  render  the  original  into 
a  corresponding  English  term  and  recourse  has  been  had    o 
he   explanatory   text.     Grimm  especially  writes  an  obscure 
style.     He  divides  accordingly  as  the  ore  forms  an  essential 
and  integral  part  of  the  walls  or  a  distinct  body.     Von  Grod- 
deck  has  in  view  the  relative  time  of  formation's  contrasted 
with   the  walls.     Grinim   afterward   empha.:.es   geometrical 
shape,  but  this  von  Groddeck  practically  does  away  with,  and 
continues  more  consistently  genetic.     His  scheme  might  ^r 
haps  come  more  appropriately  in  the  next  section. 


458 


KEMP'S  ORE  DEPOSITS. 


Pumpelly's  conception  varies  considerably  from  the  others. 
He  writes,  as  bis  full  paper  states,  in  the  belief  that  the  metals 
have  all  been  derived  primarily  from  the  ocean,  whence  thej' 
have  passed  into  sedimentary,  and,  by  fusion  of  sediments, 
into  igneous  rocks.  The  group  of  residuary  surface  deposits, 
carrying  out  as  it  does  a  favorite  idea  of  Professor  Pumpelly, 
as  set  forth  in  his  papers  on  the  secular  decay  of  rocks,  is  an 
important  distinction. 

E.  Schemes  Entirely  Based  on  Origin. 


(16) 

H.  S.  Munroe.     Used   in  the   Lectures  on  Mining  in  the 
School  of  Mines,  Columbia  University. 
I.  Of  surface  origin,  beds, 

(a)  Mechanical  (action  of  moving  water). 

1,  Placers  and  beach  deposits. 

(b)  Chemical  (deposited  in  still  water), 

1.  By  evaporation  (salt,  gypsum,  etc). 

2.  By  precipitation  (bog  ores). 

3.  Residual  deposits  from  solution  of  lime- 

stone, etc.  (hematites). 

(c)  Organic. 

1.  Vegetable  (coal,  etc), 

2.  Animal  (limestone,  etc.), 

(d)  Complex  (cannel  coal,  bog  ores,  etc). 
II.  Of  subterranean  origin. 

(a)  Filling  fissures  and  cavities  formed  mechani- 
cally, 

1,  Fissure  veins,  lodes. 

2,  Cave  deposits— lead,  silver,  iron  ores. 

3,  Gash  veins.     The  cavities  of  2  and  3  are 

enlarged  by  solution  of  limestone, 
(6)  Filling   interstitial  spaces  and  replacing  the 
walls. 

1.  Impregnated  beds. 

2.  Fahlbands. 

3.  Stock  works. 

4.  Bonanzas. 

5.  Masses. 


i 


APPENDIX  I. 


4:59 


1  mechani- 


This  scheme  covers  all  forms  of  mineral  deposits,  whether 
metalliferous  or  not,  while  most  of  those  previously 
given,  as  well  as  the  one  that  follows,  concern  only  metallifer- 
ous  bodies.  The  scheme  is  consistently  genetic  and  was  elab- 
orated because  such  an  one  filled  its  place  in  lectures  on  min- 
ing better  than  one  based  on  form.  The  general  principle  on 
which  the  main  sub-division  is  made  differs  materially  from 
any  hitherto  given.  Deposits  formed  on  the  surface  are  kept 
distinct  from  those  originating  below,  even  though  the  first 
class  may  afterward  be  buried.  It  is  immediately  after  this 
scheme  that  the  one  in  paragraph  1.06.05  finds  its  place. 

In  the  report  of  the  State  Geologist  of  Michigan  for  1801-02 
(issued  Januarj',  ISO:}),  pp.  144.  145,  Dr.  M.  E.  Wadsworth 
has  published  a  "Preliminary  Classification  of  Metalliferous 
or  Ore  Deposits."    The  main  outline  is  as  follows : 

I.  Eruptive  Deposits      («)  Non-Fragmental. 

{b)  Fragmental. 
II.  Mechanical  Deposits  («)  Unconsolidated. 

(6)  Consolidated. 
III.  Chemical  Deposits     {a)  Sublimations. 

{())  Water  Deposits. 

(c)  Impregnations  or  Replace- 

ments. 

(d)  Segregations  or  Cavity  De- 

posits. 

Each  of  the  above,  except  III.  (rf),  is  then  subdivided  so  that 
the  table  becomes  practically  a  classification  of  rooks.  Indeed, 
a  moment's  consideraton  will  show  tliat  the  scheme  in  its 
main  divisions  is  closely  modeled  after  the  prevailing  classifi- 
cation of  rocks.  III.  {d)  Segregations  or  Cavity  Deposits  con- 
tains the  following:  1.  Pockets.  2.  Chambers.  ;5.  Contact 
Deposits.  4.  Veins,  including  Gash  Veins,  Segregated  Veins, 
Reticulated  Veins  or  Stock  works,  Contact  Veins,  Fissure  or 
Fault  Veins. 

The  author  states  in  some  appended  comments  that  the  table 
is  not  limited  to  those  deposits  now  practically  worked  (which 
we  ordinarily  understand  the  expression  ore  deposits  to  mean), 
but  is  intended  to  include  all  that  have  been  or  may  be  of  value. 
But  in  this  respect  there  is  good  ground  for  preferring  to  make 


ir^ 


460 


KEMPS  ORE  VEP081T8. 


our  classifications  in  ore  deposits,  as  in  mineralogy,  zoology, 
etc.,  embrace  only  the  authenticated  varieties,  expecting  addi- 
tions to  be  incorporated  as  discovered  and  suitably  dovScribed. 

The  same  general  grouping  as  this  scheme  employs  is  inde- 
pendently adopted  by  R.  S.  Tarr,  in  the  Economic  Geology  of 
the  hnited  States,  1804. 

For  the  meeting  of  the  American  Institute  of  Mining 
Engir^^ers,  held  in  connection  with  the  various  congresses 
at  the  Vorld's  Fair  in  Chicago,  July,  1SI);5,  Professor  Franz 
Posep)  ■^f  Vienna,  contributed  a  grand  essay  on  the  "Origin 
of  Ore  Deposits. "  The  materials  for  it  were  specially  as- 
sembled '  y  Professor  Posepny  while  giving  a  course  of  lectures 
at  the  Pribram  Mining  Academy  in  the  ten  years  following 
1870.  The  paper  is  a  theoretical  discussion  of  the  origin  of 
ores,  with  illustrations  selected  from  all  parts  of  the  world, 
but  especially  from  Europe  and  America.  It  forms  one  of 
the  most  important  contributions  to  the  literature  that  has  yet 
been  made.  Posepny  distinguishes  at  the  outset  between  rocks 
and  mineral  deposits;  i.e.,  between  original  materials,  sucli 
as  wall  rock,  and  secondary  introdiictions,  such  as  veins,  etc. 
The  former  he  calls  "idiogenites,"  the  latter  "xenogenites," 
basing  the  names  on  the  familar  Greek  terms  that  run  through 
all  our  literature.  The  latter  are  especially  characterized  by 
"crustification,"  by  which  term  is  indicated  what  has  been 
called  "banded  structure,"  on  p.  47.  The  subject  of  cavities 
is  then  taken  up,  and,  while  minute  pores  are  stated  to  be  in 
all  rocks,  a  distinction  is  made  between  the  larger  openings, 
which  originate  in  a  rock  mass  as  a  part  of  its  own  structure, 
such  as  contraction  joints  in  igneous  rocks,  amygdaloids,  and 
the  like,  and  those  induced  by  outside  causes,  such  as  fault 
fissures. 

The  circulation  of  water  through  these  is  next  treated  :  first, 
surface  waters  or  "vadose"  circulations,  which  descend; 
second,  ascending  waters  from  great  depths,  such  as  springs 
in  deep  mines,  hot  springs,  etc.  The  common  salts  in  solution 
in  these  latter  are  tabulated,  being  of  course  mostly  alkaline 
carbonates,  sulphates,  chlorides,  etc.  The  "exotic"  metallic 
admixtures  which  would  bear  on  the  origin  of  ores  are  next 
discussed,  so  far  as  possible  with  analyses  of  actual  cases.  The 
alterations  produced  by  mineral  springs  in  rocks  and  the  struc- 


APPENDIX  I. 


401 


zoology, 
iug  addi- 
icribed. 
8  is  iude- 
iologij  of 

I  Mining 
congresses 
8or  Franz 
e  "Origin 
3cially  as- 
of  lectures 

following 

origin  of 
the  world, 
nis  one  of 
lat  has  yet 
:ween  rocks 
trials,  such 

veins,  etc. 
jogenites," 
uu  through 
cterizeil  by 
t   has   been 

of  cavities 
id  to  be  in 
openings, 
structure, 
iloids,  and 

ih  as   fault 

3ated:  first, 
descend ; 
as  springs 
in  solution 
tly  alkaline 
metallic 
38  are  next 
ases.    The 
the  struc- 


tural relations  of  the  deposits  of  mineral  springs,  especially  as 
expressed  by  "crustification,"  are  then  described.  This  pre- 
liminary material  clears  the  way  for  the  general  tliscussion 
of  the  origin  of  ore  bodies.  The  argument  running  all  through 
the  paper  is  that  ore  bodies,  even  when  apparently  inter  bedded 
with  sedimentary  rocks,  are  of  secondary  introduction  and,  in 
general  for  veins,  are  from  deep-seated  sources.  Precipitation 
from  descending  solutions  and  filling  by  lateral  secretion  are 
strongly  controverted. 

The  discussion  of  origin  follows  in  its  arrangement  the  fol- 
lowing classitication  of  ore  deposits: 

I.     Filling  of  spaces  of  discission  (fissures). 
II.     Filling  of  spaces  of  dissolution  in  soluble  rocks. 

III.  Metamorphic  deposits  in  soluble  rocks;  in  simple  sedi- 
ments; in  crystalline  and  eruptive  rocks. 

IV.  Hysteromorphic  {i.e.,  later  or  last  formed)  deposits. 
Secondary  deposits  due  to  surface  action  {i.e.,  placers,  etc.). 

The  treatment,  both  in  the  introductory  pages  and  in  the 
later  discussions,  is  often  strikingly  similar  to  that  of  this  book, 
and  the  underlying  argument  is  much  the  same.  The  stand- 
point in  both  essays  is  essentially  a  genetic  one,  and  the  main 
difference  lies  in  the  fact  that  the  one  is  an  exposition  of  an  in- 
dividual's views,  fortified  by  examples  from  all  parts  of  the 
world;  the  other  endeavors  to  be  a  judicial  statement,  with  a 
fairly  complete  description  of  the  ore  bodies  of  the  United 
States  and  Canada  alone.  The  writer  differs  with  Posepny 
however  in  the  greater  weight  given  to  the  ores  of  igneous 
origin. 

l.()(i.28.  An  extended  treatise  on  the  useful  minerals,  earthy 
as  well  as  metallic,  by  MM.  E.  Fuchs  and  L.  De  Launay,  has 
recently  appeared  {Traite  des  Gttes  Mineraux  et  Metalli- 
feres,  Paris,  18'.K3).  The  book  is  based  on  the  lectures  on 
economic  geology  delivered  in  the  Ecole  Superieure  des  Mines, 
at  Paris,  in  the  last  fifteen  years  by  the  two  authors.  (Pro- 
fessor Fuchs  died  in  1881),  and  was  succeeded  by  Professor  De 
Launay.)  A  vast  amount  o"f  valuable  information  is  brought 
together  and  discussed  from  various  points  of  view,  useful 
applications  and  methods  of  treatment  being  set  forth  as  well 
as  geological  occurrence.     The  work  i&  encyclopedic  in  scope 


462 


KEMP'S  ORE  DEPOSITS. 


j 


■  I 


and  affords  a  reader  descriptions  of  niiiieral  resources  and  refer- 
(inces  to  their  literature  in  every  <juHrt«>r  of  the  world.  So  far, 
iiowever,  as  tho  United  States  are  concerned  the  authors  have 
suffered  from  tho  unavoidahle  limitations  of  those  not  native 
and  conversant  in  a  discriminating  way  with  our  literature. 
Nevertheless  they  have  endeavored  to  give  a  large  share  of 
their  space  to  this  countr}',  and  where  prominent  monographs 
have  appeared  they  have  been  read  with  care,  but  in  many 
cases  reference  to  later  papers  and  descriptions  would  have  im- 
proved the  text.     A  later  edition  will  doubtless  correct  these. 

The  classification  of  ore  deposits  as  well  as  other 
useful  minerals  on  a  genetic  principle  has  evidently  been  in 
many  minds  in  the  last  few  years.  Mr.  Frederick  Danvers 
Power,' of  Melbourne,  Victoria,  reviewed  the  subject  in  \Wl, 
and  after  giving  the  schemes  of  others  and  summing  up  the 
various  characteristics  of  veins,  has  formulated  a  classification 
whose  main  divisions  are  as  follows:  I.  Contemporaneous; 
Indigenous.  II.  Metasomatic  or  Chemical  Alteration  of  the 
Original  Constituents.  III.  Subsecjuently  Introduced ;  Exotic. 
Each  of  these  has  then  a  number  of  subdivisions  too  numerous 
to  be  repeated  here. 

Prof.  William  O.  Crosby,"  of  Boston,  has  recently  discussed 
the  same  subject  in  a  very  suggestive  way.  The  main  head- 
ings are:  A.  Deposits  of  Igneous  Origin  (Igneous  rocks) ;  B. 
Deposits  of  Aqueo-Igneous  Origin ;  C.  Deposits  of  Aqueous 
Origin.  The  first  and  last  are  then  subdivided  at  considera- 
ble length,  but  the  second  is  chiefly  limited  to  the  pegmatite 
(granitic)  veins  which  attend  many  plutonic  intrusions.  Lack 
of  space  prevents  the  full  reproduction  of  bofh  these  schemes, 
but  sufficient  has  been  mentioned,  it  is  hoped,  to  indicate  tho 
line  of  attack  and  to  place  a  reader  desiring  to  look  the  sub- 
ject up  in  touch  with  the  originals. 

'  "TheClassifltiation  of  Valuable  Mineral  Deposits,"  Trans.  Audralas. 
Inst.  Mill.  Eiuf.,  1892. 

"  "A  Classification  of  Economic  Geological  Deposits  based  on  Origin 
and  Original  Structiire."  Aviei'.  Oeol.,  April,  1894,  p.  240.  The  paper  also 
appears  in  the  Technological  Quarterly, 


and  refer- 
So  far, 
bors  have 
ot  native 
iterature. 

share  of 
mographs 
in  many 
have  ina- 
jt  these, 
as  other 
[y  been  in 

Danvers 
t  in  1892, 
g  up  the 
isitication 
oraueoiis; 
on  of  the 
;  Exotic. 
Qumerous 

discussed 
ain  head- 
ocks) ;  B. 

Aqueous 
ionsidera- 
segmatite 
IS.     Lack 

schemes, 
licate  the 

the  sub- 

Australas. 

on  Origin 
paper  also 


INDEX. 


Abiquui,  N.  M.,  cojjjier  ores,  224 
Acadian  staj^e,  4. 
A(lair.sville,  (ia.,  aluminum,  404 
Adams    F.  J).,  „„  ores  of  Treadwell 

Mnie,  ;i!)l. 
Adams  Co.,  J'enn.,  limonites.  104 
Adams  Co.,  Ohio,   Clinton   ores  'lI4 

1 1 5. 

A.liroM.lafks,  N.  Y..  ma-netites,  Kio 
Admu-alty  Islands,  Alaska,  gold  de- 
posits, ;j!»2. 
AggloiiKM-atcs.  ^>,S1. 

AinsNvorth  nistrict.  B.  Cgcld  mines, 
o!M,  .i!).). 

Alabama,  aluminum,  (bauxite),  404 
Clinton  ore,  114,  117. 
Copper,   1{»4. 
(iold  mines,  ;)T8. 
Limonite.s,  104. 
Tin  ores,  444. 
Alaska,  geology  of,  385. 

Cold,  :m: 

Treadwell  niine.s,  300. 
Alder  Guleh,    Madi.son    Co.,    Mont. 

ol  (, 

Aleutian  Islands.  Ala,ska,  385. 
Algonkian  sy.stem,  4. 
Allamakee  Co..  Iowa,  limonite,  98,  99 
A  inaden.  Spain,  mercury,  434 
AIno,  .Sweden,  (il,  17,5 
Altuinine,  Jetierson  Co.,  Mont.,  317 
AlturasCo.,  Idaho,  327. 
Aluimnum,  in  bauxite,  404 
Origin,  404-410. 
Soiu-ce.s,  403. 
Ainador  Co.,  Cal..  copper  mines,  19o 
Ammikie  series,  4. 
Annie  Lee  nnne,  Colo.,  398,  305 
Anthonys  Nose,  N.  Y.,   nickel'  ores, 
430. 
•  Pyrite  ores,  184. 
Anticlines,  arrested,  11, 
Detined,  11. 

With  shattered  bend.s,  17  19 
Antigonish  Co.,  Nova  Scotia,  hema- 
tite, 120. 


Antimony,  410 

Apache  Co     Ariz.,  .silver  and  gold 

ores,  335.  " 

Ai)oll(,^  mine,   ijnga  Island,  Alaska, 

Appalachians,  general  de8crii)ti(m  7 
(-eology  of  jr,,|,i  ,|,.,,o.sits,  376  '  * 
iMaiiganese  ores,  418 

Appendix,  447. 

liemaiks  on.  448. 
Appleton.  Wis.,  fold  at,  20 
ArcluNin  Croup,  classification,  4 
Argentine,    Clear  Creek   Co.,    Colo., 
™:0.).  ' 

Arizona,  copinsr  mines,  214-230 
Geology,  334. 
Cold  deposits.  334. 
Lead  silver  ore.s.  279. 
.Silver  deposits.  334. 
Arkaiisa.s,  aiUimony,  411, 
Bauxite.  404-4()(i. 
Iron  ores,  9(1,  97. 
Manganese,  420, 
Nickel,  440. 
Silver  mines,  283. 
Arksnt  Fjord,  (; leenland,  403 

Annstead  HI..    Jr.,  gold   ores,  of 

Idaho,  324 
ArroNs-^Lakes.  li.  C,  upjier  and  lower, 

Arsenic^  depo.sits,  412. 

{Si'e  Gold  in  Canada. ) 
Ascension  by  infiltration.  40,  41-43 
^Vshcroft  iron  mines,  Colo     170 
Ashliuid  luine,  Ironvvood,  Mich'    142 
Asi)en,  Pitkiu  Co.,  Colo.,  45 
Iron  mines,  170. 
Lead  and  silver,  268 
Atlanta,  Elmore  Co.,  Idaho,  335, 
Atlantic  Border  gold,  283 
Lead,  220. 
Silver,  283. 
Augusta  Co    Va.,  manganese,  418. 
Auriferous  beach  sands.  348 
Gravel,'^.  353. 


464  INDEX. 


Austin,  Nev.,  antimony,  411. 
Gold  and  silvor  ()r»\s,  \V,\\). 
Avulu,  .Sorvia,  nieri'ury,  424. 


MiL-Iielor  Mt.,  Colo.,  203. 
bilker  Co.,  Ore.,  '<\\'i. 
Cold  niinoH,  i}4H. 
Diild  Butte  (iroup,  Deer  Lodge  Co., 

Mont.,  :W0. 
Baldy  Mt..  Utah,  ;{:{:{. 
Haltiinoro  HeKion,  trliroiuite,  414. 
KandtMl  striuiture  of  veins,  47. 
Maniiai'k  City,  Mont.,  Ml. 
Haulier  di.striet.  Id.ilio,  IW."). 
Barker  miriiiif;  di.slriut,  Meagher  Co., 

Moiit.,  ;«(»,  ;J2l. 
Barton  lliil,  N.  Y.,  magnetite,  1((3. 
Barns,   ('.,    on  eleetrieal  aetivity   in 
veins,  .")2,  ."liJ. 
Exjwriments  on    tiie    Comstock 
Lode,  84;$. 
BasJil  granite.  UMS. 
Bassiek  mine.  (Jolo..  4T.  49.  m.  900. 
Batesville.  .Vrk..  manganese,  4'3(). 
BatliCo.,  Kv.,  C!iinton  ores,  U.'i. 
iiattle  Mt.,  teller  Co.,  Colo.,  UU,"). 
Bauxite,  40t-40;. 
Bay  ley.  \W.  S..  on  Michigan  iron  ores, 

127.  120. 
Bear  Lake  t  !o. ,  Idaho.  ;{27. 
Bearpaw  Mt..  Mont..  828. 
Beaver  Co..  TTtali.  gold  and  silver,  8.38. 
Beaver! lead  (Jo.,  Mont.,  gold  and  sil- 
ver, 81 4'. 
Becker,  C    F.,  on  Alaska  mines,  890. 
On  (iinnabf.r,  80,  44,  878. 
On  Comstock  Lode,  origin,  840- 

344. 
On  gold  ores,  35,  8Tfi,  378. 
On  gold  in  Mad  Ox  mine,  Cal, 

808. 
On  gravel  beds,  Cal.,  356. 
On  Joints,  15. 
On  (juicksilver,  425. 
On  silver  ores,  85. 
On  Soret's  principle,  67. 
On  Sulphur  Bank  mine,  437. 
On  Washoe  rocks,  845. 
Beds  defined,  6. 
Bell,   Robert,    on   Hudson   Bay  gold 

ores,  888. 
Belmont,  Nev.,  eold  and  silver  ores, 

888. 
Belt  formation  of  Montana,  315. 
Bench  gravels,  Alaska.,  808. 
Bennet  mines,  Alaska,  802. 
Benson  mine,  N.  Y. ,  iron  ores,  166. 
Benton  stage,  5. 
Berks  Co.,  Penu.,  iron  ores,  109. 


Bernallilo  Co., 
B(*rner'.s  Bay, 


N.  M.,  280. 
Alaska,  goM. 


802. 


Bertha  mine.s,  V'a.,  zinc,  217. 
Bessemer    limit    of    Lake    Superior 

ores,  H"). 
Beulidi  antimony  mine,  Nev.,  411. 
Big  Cottonwood  Cailou,  Utah,  274. 
Big  Creek,  Nev.,  411. 
Big  Mill,  IVmu.,  175. 
Bingham  CaAon.  Utah.  830. 
Bingham  Co.,  Utifh,  274. 
Birch  Creek  .series,  888. 
Birmingham  di.strict,  Ala.,  iron  ores, 

IIH. 
Bishee,  Ariz.,  ropiH-r,  217. 

Wegion,  gold  and  .silver,  880, 
Bischoll',  on  silictate  of  gold,  373. 
Bismuth,  412. 

Bitter  Root  Mts..  Idaho,  323. 
Black  baud  iron  ore,  107. 
Blatrk  Hills,  S.  I).,  57. 

(ieology,  800. 

(Jold  in  I'otsdam,  309. 

I'la,cer.s,  800. 

Tin,  442. 
Black  Hornet  district.  Idaho,  82,5. 
Black  l..iike  asbestos  mine,  41(». 
Black  range  coplter  miues,  Ariz.,  230. 
Blake,    \V.    1'.,    aluminum    dei)osits, 
N.  M.,  407. 

Antimony  ores,  Utah,  411 

Copper  Basin  ores,  Ariz.,  221. 

Deep  Creek  ores,  Utah,  882. 

(Jold  and  silver.  Tombstone,  886. 

Lead  and  zinc  ores,  280. 

Mercury,  Texas,  428. 

Silver  King  mine,  Ariz.,  336. 

Zinc  ores,  N.  M.,  2.59. 
Blanco  .stage,  5. 
Blende  in  the  Rocky  Mts.,  258. 
Bleziird  mine,  Ontario,  480. 
Block  iron  ore.  107. 
Block  Island,  R.  I. ,  magnetite  sands, 

181. 
Blow,  A.  A.,  cited  on  faults.  21,  33. 

Origin  Leadville  ores,  2()5. 
Blue  lead  in  Cal.,  gravels,  855. 
Blue  Mts..  Oregim,  847. 
Bodie.  Cal.  gohl  and  silver,  353. 
B(}g  iron  ore.  87-08. 
Boi.se  districrt,  Idaho,  325. 
Bonanza  City,  Idaho,  32."i 
Bonanza,  deiined,  40 
Bonne  Terre,  Mo.,  1< 
Bonneville.  Lake,  Ni         ..J*. 
Bonsacks,  Va.,  illnsti       >n  of  g'      in, 
51. 
Zinc  mines,  249. 
Boss  of  igneous  rock  defined,  1<J. 
Boston  Mt.,  Ark.,  421. 


s     < 

I 


INDEX. 


465 


1. 

,    Superior 

pv..  411. 
tah,  274. 


,  iron  ores, 


er,  ftBft. 
)ld,  372. 

323. 


)S). 


[(laho,  32."). 

lu',  41('). 

,u;s.  Ariz..  220. 

mill    deposits, 

tah.  411. 
Ariz.,  231. 
flab.  iW2. 
)inV)stoiie.  336. 
,  230. 

^\riz.,  336. 

Its.,  258. 
436. 

ignetite  sands, 

faults.  21,  22. 
,  2»i.'). 

3l9,  3.").'). 

fclver,  353. 


ksr. 


)ii 


Ofg' 


jflned, 


Boulder  rf».,  O  )!(>.,  306. 
Iron  ores    10)1.  170 
Box  Klder  (•<;  .  Utiili,  320. 
Boy.l,   ('    IC  ,  Hcrtliu  mine  zino  ores, 

24  s. 
On  ])n)dticti()n  ul'  liig  Hill  mine, 

Penn.,  17». 
Boye,  Dr.,  iron  ores,  103. 
Hoyertown,  I'eiin.,  iron  mines,  170. 
Brailley.  K.  P.,  on  limonites,  104. 
Krandon,  Vt.,  iron  ores.  100. 

Manganese  on>s,  41!^. 
Brainier.  .1.  (".,   orij^in  of,  Ark.,  alu 

milium,  400. 
Brazil,  iioii  ores,  17."». 
Hrewer  mine.  S.  C.  3H0. 
Bridal  (•lianil)er  mine,  N.  M.,  361. 
.Hridtj;»'r  stage,  .5. 

Bristol.  Conn.,  copper  depo.sits,  233. 
Britisli  Columliia  gold  gravels,  324. 

Platinum,  441. 
Britton,  X.  \,.,  on  Staten   Island  bog 

ores,  01. 
Alagnetile  ores,  N.  Y..  167. 
Broadwater  Co.,  Mont.,  310. 
Brooks,  T.  B. .  on  Marcpiette  district, 

13.'). 
Browne,   D.   H.,   on  isocheniio   lines, 

183, 
Browne,  R.  E.,  on  California  gravels' 

361. 
Bryant,  Ark  .  .ilnminum,  400. 
Bucks  Co.,  Pctui.,  iron  ore,   HiO, 
liuikwlieat  zinc  mine,  N.  ,1.,  3.")3. 
Buena   Vista    mine,   Cripple    Creek, 

Colo.,  305. 
\M\\\  Domingo  mine,  Q)lo.,  49,  297. 
Bull  Mt..  Colo.,  30.'). 
Burden  spathic  ore  mines,   Hudson. 

N,  Y.,  110. 
l^urraBurra  mine.  Teun.,  193. 
I  urro  j\lt..  New  Mexico,  285. 
Piitte,  Mont.,  30,  44,  51,  ,58.  315. 
Copjier  ores.  I'.tO,  1!»9,  200,  202. 
Development  of.  200. 
Placers  near,  354. 

C. 

Calavei-as  Co    Ciil,  195. 

<  iildwell   Co..    Ky.,    lead    and    zinc 

mines,  230. 
Caledonia,  iron  min«>s,  ^lo.,  125. 
Calico,  silver  (list  rict,  Cjd..  351. 
California  B.ir.  Idaho,  324. 
'   difornia,  antimonv,  410;  chromite, 
41.5. 

Copper  mines,  19,5. 

Geologv.  349. 

(4old  -iavels,  3.53.  300,  361. 

Gulc      near  lieadvillc.  Colo.,  395 


California,  licad  silver  ores,  379. 
Magnetite.  171. 
Mercurv,  424. 
Platinum.  411. 
Tin.  325. 
Gallon,  on  scheme  of  classitication  of 

ore  deposits,  452. 
Calloway  ('o.,  Tenn..  193. 
Calumet    and    Ilecia  copiK^r  mines, 

Mi(di.,  20M. 
Calvin,  H.,  on  limonites,  99. 
{ '!imliriiin  svstem,  4. 
C.imphcll  .Mt..  Colo..  393. 
CMru|)licll,  .1    !,..  on  limonites,  94. 
('amp  I'loyd  district.  I'tah,  330. 
CampoSeco.  C.il.,  <-opper  mine,  196. 
Caiiiida,  gold,  400,  412. 

Magnetite  ore  mines,  l(i6,  173. 
Canadian  Northwest,  geology,  385. 

Series.  4. 
Canon  Citv,  Colo.,  zinc  work.s,  3.58. 

Diahio,  Ariz.,  10. 
Cape  .Ami  granite,  13,  11. 
Cape  Breton,  Nova  .Scotia,  gold  ores, 
307. 
Manganese  ores,  493. 
Cap«'lton.  (^>uel)ec,  jiyrite  mine,  184. 
Carhoiiiit**  iron  ortvs.  107. 
Lead  silver,  S.  D..  373. 
Lead  silver,  Utah.  370. 
Carhoiiiferous  .series,  5. 

System.  5. 
Carbonic  ai'id  in  subterraneiin  waters, 

38. 
Caribou  Hill.  Colo.,  magnetite.  174. 
Carlyle,  W.  A  ,  on  Slocan  veins,  39.5. 
Carolinian  gohl  belt,  liTH. 
Car|)eiiter,  P.  R.,  on  Black  Hills  tin, 

443. 
Carroll  Co..  IMd.,  iron  ore,  103. 

Va..  iron  ore,  103. 
Cartersville,  <ia.,  manganese,  418. 
Cascade  Co.,  Mont.,  331. 

Mts.,  Cal.,  340. 
Casiaria,    Durango,   Mex.,   tin   ores, 

444. 
Cason  iiropert.v.  Ark..  431. 
Ca.ssia  Co.,  Idaho.  327. 
Cassiar  district,  .\laska,  393. 
Cassiterite,  441. 

Ca.stillo  Co..  Colo.,  magnetite,  170. 
Castle  Mts.  district,  Mont.,  .320. 
Cave  mine,  Utah,  lead  silver  ore,  .58, 

270. 
Cave  .Spring  manganese  mines,  f!a., 

430. 
Cavities,     secondary     uiodifications, 

36. 
Cavuga  Co..  N.  Y.,  Clinton  iron  ores, 
11.5. 


4G6 


INDEX. 


Cazin,  F.  M.  7.,  on  Silver  Reef,  Utah, 

ores,  J5;5;5. 
Cebolla    district,    Colo.,     magnetite, 

175. 
Cedar  Mt..  Mo.,  157. 
Cenozoic  (ivoup,  5. 
Central  Ciilifornia,  ;U9. 
Central  district.  Mich.,  cojtper,  208. 
Cerro  de  Mercado,  Mex.,  iron  ore.s, 

187. 
Cerro  Gordo  district,  Cal.,  353. 
Chaffee  Co.,  CJoh).,  395. 

Magnetite,  170. 
Chalco{)yrite,   of  igneous  origin,  61- 
(55. 

With  ])yrite.  180. 
Chamber  dei)osits,  58. 
Chaml)erlin,  T.  C,  ()8. 

On  Lead  ores,  3:55,  236. 
Cliamj)laiu  sei'ies,  5. 
Chantller  and  Pioneer  mines,  Minn., 

148. 
Chapin  mine,  Mich.,  138. 
Cliarlemuiit,  Ma.ss.,  i)yrite  mines,  184. 
Charles  Dickens  mine,  325, 
Cliateangay  iron  mines,  N.  Y.,  85. 
Chatham,  ijonn.,  nickel  ore,  430. 
Cluittahoochee  stage,  5. 
Chattanooga,  Tenn.,  ii'on  ores,  117. 
Chauuiere  River,  Can.,  gold  gravels, 

400. 
Chauveuet,   R.,  on  Colorado  magne- 
tite, 170. 

Iron  ores.  98. 
Chazv  stage,  4. 
Cheever  mine,  N.  Y.,  162. 
Chemung  series,  5. 
Cherokee  I  o. ,  Kansa.s,  240. 
Cherry  Creek,  Mo.,  315. 
Cherry  Valley,  Mo.,  123. 
Chester,  A.  11.,  on  yield  of  standard 
iron  ores,  85. 

Co.,  Penn..  aluminum  ores,  407. 

F.  D.,  on  chromite,  415. 

Mass.,  alumium  deposits.  410. 
Chibas.  E.  J.  gold  mining,  Columbia, 

299. 
Chico  stage,  5. 
Chii)ola  stage.  5. 
Chisholm,  F.  F.,  on  Cuban  iron  ore, 

1H7. 
Choteau  Co.,  Mont.,  322. 
Chromite,  analysis,  414. 

Dissemination  in  ser])entine,  414. 

Of  igneous  origin.  01,  03. 

U.se.s.  414. 
Chromiinn.  412. 
Chugwater   Creek,  Wyo.,  iron  ore.s, 

171. 
Churchill  Co.,  Nev.,  silver  ores,  340. 


Church,  J.   A.,  on  Comstock  Lode, 
340, 

On  faults,  24. 
Chutes,  49. 
Cincinnati  stage,  4. 

Uplift,  9. 
Cinnal)ar,  424. 
Claiborne  stage,  5. 
Clarke  Co.,  Mont.,  320. 
Clarke,  E.,  on  lead-silver  ores,   Lake 

Valley,  N.  M.,  201 
Clarke,  F.  W.,  on  earth  s  crust,  447. 
Clarke  Timber  Reserve,  Mont.,  321. 
Classitication  of  ore  deposits,  447. 
Clay,  attrition,  in  a  vein,  49, 

Ironstone,  106. 

Sean  .  selvage,  49. 
Clavtcm,  J.  E.,  cited,  49,  319. 
Clear  Creek  Co.,  Colo.,  306. 
Clear  Lake,  Cal.,  427. 
Clei'c,  F.   L.,  on  Missouri  ores,  240, 

242. 
Cliff  copper  mine,  IVIich..  208. 
("lifton  copper  district.  Ariz.,  336. 
Clinton  Co.,  Ohio,  114. 

Ores,  5*.  114,  121,  446. 

Stiige,  4. 
Coal   measines.   classification    of,  in 

Penn.,  107. 
Cotistal  Plain,  7,  376. 
Coast  Range,  Cal.,  349,  445. 

jMercury,  424. 
Cobalt,  in  Sudbury  Region,  438. 

{See  nickel,  416.) 
Cochise  Co.,  Ariz.,  lead-silver,  279. 
Cteur  d'Alene,  Idaho,  lead-silver  ores. 

274,  324 
Colfax  Co.,   N.  M.,   silver  and  gold. 

286. 
(A)loml)ia,  South  America,  441. 
Colorado,  Creeile,  gold  ores,  293. 

(ieology,  286. 

Iron  ores.  98,  170,  174. 

Lead-.silver  mines,  262-272. 

.u.ignetite.  170. 

Plateau,  445. 

Stage,  5. 

Silver  and  gold,  286-307. 
Columbia  Co.,  N.  Y.,  lead  ores,  227 

Limonites,  101. 
Columbia  Hill,  Cal..  gold  gravels,  854. 

Mines,  Idalio,  324. 

River  district,  B.  C,  394. 
Comanche  stage,  5. 
CommonwealMi  mines,  Mich.,  138. 
Comstock  Lode,  20,  35. 

(Jeology  of,  340-345. 
Comstock,   T.   B.,   on  Colorado  gold 
ores,  2H8, 

On  Colorado  lead-silver  ores,  722. 


INDEX 


467 


itock  Lode. 


er  ores,  Lake 

IS  crust,  447. 
Mont.,  '-i^l- 
posits,  447. 
ill,  49. 


t9,  319. 
,  '30B. 

5ouri  ores,  240, 

\i\\.,  208. 

t,  Ariz-,  336. 

4. 

,446. 

silication    of,  in 


49,  44r). 

egiou,  438. 

^ua  silver,  279. 
leiul-silverores. 

silver  and  gold. 

lierica.  441. 
jlil  ores,  293. 

|0,  174.      ^ 
3S,  262-272. 


lead  ores,  -i-i 
Lold  gravels,  354. 
|i.  C.  394. 
lies.  ^lich.,  138. 

|,n  Colorado  goM 
Id-silver  ores.  723. 


Conejos  Co.,  Colo..  296. 
Conneoticnit  bisnuitli,  412. 

Coi>i)er  contact  deposits,  228. 

Lea«i  mines.  227. 

liinionite.  101. 

Nickel  ores,  4:?0. 
Contact  deposits.  .")S,  09. 
Continental  divide,  ;521. 

Montana,  :il."). 
Coosji  Valley,  Ca.,  aluminum,  404. 
(;o])per  Hasin,  Ariz..  22(1. 
Copi)er  Clitl'  mine.  Out.,  436. 
Copper  Creek.  Colo.,  294. 
Copper  districts  in  Arizona,  221. 
CopiKM-  Falls  district.  Mich.,  208. 
(  opper  >lt.,  Ariz..  21."). 
C()p])ei()]iolis,  Cal..  l!l(i. 
( 'opjieropolis  mine.  Ctah.  221. 
Copper  ores,  analysis,  1H!». 

Discovery  of.  in  Michigan,  211. 

In  mine  waters,  .")2. 

In  sandstone,  222,  223. 

Origin  of,  2(»9. 
Copiier,  tables  of  production,  82,  90, 

97,  22.J. 
Corniferous  stage,  5. 
Cornwall,  Penn..  iron  mines,  85,  175. 
Cortland  series,  (il. 
Corundum  of  igneous  origin,  .56,  61,  63. 
Cotta.  B.  von,  cited,  451. 

On  metiiod  01  vein  filling.  39. 

On  schemes  of  classilication    of 
deposits,  449. 
Courtis,  W.  M.,  on  gold  (piartz  363. 
Cow  Bay.  Nov;i  Scotia,  ;')99. 
Cramer,  F. ,  on  faults,  20. 
Craidierry,  N.  ('..  magnetite.  169. 
Crawford  Co.,   ]\lo. ,    liematites.     69, 

122. 
Credner.  H.,  on  origin  of  Marquette 

ores,  185. 
Creede,  Colo.,  29:i. 

Crescent  mine,  Utali,  lead-silver,  275. 
Cretaceous  system,  5. 
Crimora,  Va.,  manganese,  418. 
Cripple  Creek,  Colo.,  ;{0(). 
Cri])ple  Creek.  \'a.,  iron  ores,  102. 
( 'ri.smon    IManunoth     copper     mine, 
Ctah,  221.  ^ 

Lead  silv(»r.  275. 
Crittenden  Co.,   Ky.,  lead  and  zinc 

ores.  2:59. 
Crosby.  W.  O  ,  on  joints,  1.5. 
Cross."  \V.,  Bas.sick  mine.  297. 

Map  of  Telluride.  Colo.,  290. 

Pike's  Peak  deposits,  804. 
Cinstitication.  47. 
Cnb;i,  iron  mines,  ISfi. 
l'und)erland  mine,  ^lont.    820. 
Cimiherlaud  ii'on  mine,  R.  I.,  173. 


Cumberland.  R.  I.,  peridotite.  .56.  61. 
Curry  Co.,  Ore.,  gold  gravels,  848. 
Curtis,  J.  S.,  44,  46. 

r^ureka,  Nev.,  277. 

Metasomatic  interchange,  82. 

Silver  in  porp'iyry,  85. 
Cashing,  H.  I".,  discovery  of  augite 

syenite.s,  161. 
Custer  Co. ,  Colo. ,  296. 

Idaho,  824. 
Custer  mines,  Idaho,  325. 

D 

Dacy  Flat.  S.  D.,  813. 

Dade  Co.,  Mo.,  69. 

Dahhmega,  (Ja..  gold  deposits,  377. 

Dakotti  stafije,  5. 

Dall,  W.  11.,  on  Alaska,  888. 

Daly  West  mine.  Utah.  829. 

Dana,  J.  1).,  on   limonites  of  N.   Y., 

105. 
Daubree,  on  joints,  15. 

Tin  ores,  70. 

Water  in  rocks,  27  ?8. 
Davidson.  Mt.,  Nev.,  840. 
Davis  Creek,  Va.,  108. 
Davison  Co.,  N.  C.,  lead  deposits.  228. 
Dawson,  (i.  M..  888. 

Kootenay  I-ake.  rock  series,  394. 

Origin  of  gold.  Alaska,  875. 
Dav.  John,  stage,  5. 
Deinhvood  (iulch.  S.  D.,  810. 
Dean  iron  nunes,  N.  Y.,  167. 
Dease  l.<ike,  gold  mines,  Alaska,  894. 
Deep  Creek,  Utah,  lead-silver  mines, 
275. 

.Silver  and  gold  mines,  382. 
Deep  gravels,  California,  8^4. 
Dee})  River,  N.  C,  iron  ores,  109. 
Deep  River  stage,  5. 
Deer  Lodge  Co..  Mont.,  819. 
Deer  Trail  mine.  Utah,  888. 
De  ia  Beclie.  on  formation  of  veins,53. 
De  Launay.  L..  on  vein  fillings,  38. 
Delaware,  chromite.  414. 
Del  Norte  Co.,  Cal..  cln-omite,  415. 
Deloro,  Can.,  arsenic  mine,  412. 
Dent  Co..  IMo.,  iron  ores.  128. 
Devereux.    W.    B. .    gold    gravels  of 
Black  Hills,  811. 

Magnetites  of  Colo.,  70. 
DeAoiiian  svstem.  4. 
Diadem  Lode.  Cal..  86H. 
Dianunid  Hill  mines,  .Mont.,  819 
Dike,  defined,  12. 

Diller,  J.  8.,  on  Casca<le  Range,  Cal., 
349. 

Geologv  of  Sierras,  Cal.,  8.59. 

Gold,  Miuersville,  Cal  .  809. 

Lead  and  zinc,  Kv.,  289. 


408 


INDEX. 


Diller,  J.  S.,  on  Nickel  ores,  origin  of, 

439. 

Sandstone  dikes,  450. 
Dillslmrjjj  mines,  Penn.,  179. 
d'Invilliers,  E.  V.,  on  Big  Hill  mine, 

Penn.,  ITS. 
l)is.senu  Milted  ore.s.  .57. 
Dodge  Co.,  Wis. ,  iron  ores.  114. 
Doe  Kuii  Mo.,  lead  mines,  228. 
Doloniitization.  82. 
DoloresCo.,  Colo.,  gold  and  silver,  287. 
Dona  Ana,  Co.,  N.  M.,  2()0. 
Don,  J.  R.,  on  Australian  gold  Depo- 
sits, 2S2. 

Occurrence  of  gold  in  sea  water, 
;}7:5. 
Donald,  J.  T.  on  chromite.  416. 
Douglass  Island,  Alaska,  JJOo,  ;!!H). 
Douglass,  James,    on  Bisbee  Copiier 

ores,  217. 
Drinker,   H.  S.,  zinc  ores  of  Penn., 

251. 
Dnindinnmon  mines.  Mont.,  320. 
Dry  Canon  mines,  Utah.   '^5,  330. 
Ducktowii,  Tenn.,  51,  KKi. 

Clialc<)i)yrite  mines,  190. 

Pvrite  mines,  184. 
Dutclless  Co.,  N.  Y.,  limonites,  101. 
Dutton.  Capt.  C.  E.,  on  geology  of  N. 

M.,  284. 
Dj'estone  iron  ore,  114. 

E. 

Eagle  Co..  Colo..  294. 

Eagle  Hill,  porphyry.  Utah,  330. 

Eagle  River,  Colo.,  208. 

Eakins,  li.  G.,  on  eruptive  rocks,  35. 

East  Tenn.,  mine,  192. 

East  Tintic   district,  Utah,  limonite, 

100. 
Eastern  sandstone,  Keweenaw  Point, 

Mich.,  205. 
Egan  Canr.n,  Nev..  339. 
Egleston.  T.,  on  .solubility  of  gold,  373. 
El  Dorado  Co..  Cal.,  303. 
Electrical  atrtivitv  of  veins,  52. 
Klizal)ethto\vn,  N.  Y.,  172. 
Elk  ^It  .  C<;lo.,  iron  ores.  170. 
Elkliorn  mine.  Mont..  58,  317. 
Elko  Co. .  Nev..  silver  (»res,  340. 
Ehnore  Co.,  Idaho,  325. 
El  Paso.  Texas,  tin  ores.  444. 
Ely  c<)))per  mine,  Vt.,  190. 
Ely,  Minn.,  iron  ores.  144,  150. 
Ennna  mine,  Utah,  275. 
Emmons,  S.  F.,  on  Bassick  mine  ores, 
297. 

On  Butte  coj)iier  ot».      '07. 

On  contact  deposits,  07. 

On  hematite  ores,  124. 


Emmons,  S.  F. .  on  Lead-silver  ores  of 

Colo..  270.  272. 

On  Leadville  ores,  263.  265. 

On  metasomatic  interchange,  32. 

On  replacements,  44. 

On  silver  ores,  35. 
Endlich,   F.    M.,   on   gold    mines  of 

Colo.,  28S. 
Enriquitii  mercury  mine.  Cal.,  420. 
Enterprise,  Mis.s. ,  iron  ores.  109. 
Eocene  series,  5. 
Esmeralda  Co. ,  Nev.,  340. 
Eureka,  Nev.,  35,  51. 

Aragonite.  40. 

Lead-silver  ores,  277. 

Silver  and  gold.  339. 
Europe,  mercury  of,  424. 
Eutaw  stage,  5. 
Evans  nickel  mine.  Ont..  436. 
Evigtok,  Greenland,  aluminum,  403 
"Fwige  Teufe',  26. 
P'ahlband.s,  d(>Hned,  73. 

Related  to  zones,  17. 
Fairbanks,  II.  W..  on  Cal.,  gold  depo- 
sits, 359.  307. 

Tin  dei)osit.s,  443. 
Farisli.  J.  B. .    on   veins  at  Newman 

Hill,  Colo.,  290. 
Faults.  17-25. 
Fayette  Co..  Penn.,  108. 
Feich  :Mt.,  district  IMich.,  139. 
P'ergusCo. .  Mont.,  322. 
Finlav.  J.  R.,  on  iron  ores  of  Penokee- 

"(Jogebic.  144-150. 
Flagstaff  mine.  Utah,  275. 
Flathead  Co.,  Jlont..  331. 
Flat  River  district.  Mo.,  338. 
Floetze.  delined,  55. 
Florence  mines,  Mich.,  138. 
Floridian  stage.  5. 
Fhutan,  delined,  49. 
Foerste,  A.  1  . .  on  Clinton  ores,  120. 
Folds,  defined.  11,  12. 
Forest  tj)ueeM  mine,  Colo.,  294. 
Formation,  defined.  6. 
Fortunn  mine,  Ariz.,  337. 
Forty  mile  .series.  388. 
Foster,  on  iron  ores  of  Mich.,  135. 
Fonrnet's  series,  (i(i. 
Fox  Hill  stage,  5. 

Franklin  copi)er  mines,  Jfich.,  208. 
Franklin   Cc      Mo.,    lead    and    zinc 

mines.  239. 
Franklin,  Co  .  Va.,  magnetite,  109. 
Franklin   Furnace,    N.  J.,  ii-on  oris, 

167. 
Franklin  Furnace,  N.  J.,  Zinc  251-2.")7. 
Frazer.  P.,  on  Penn.  limonites,  104. 
Frederick  Co.,  Md.,  limonites,  l'*'?. 
Fremont  Co.,  Colo.,  magnetite,  ITH 


INDEX. 


469 


ilver  ores  of 

3.  365. 
rchange,  Ai- 


a    mines  of 

,  Cal..  420. 
res.  109. 

I). 


;.,  436. 
uminum,  403 


:al.,  gold  depo- 
ts at  Newinau 


Ki..  139. 
oresofPenoket' 


275. 
t«l. 

..,  228. 

.,  138. 

iton  ores,  120 
[olo.,  294. 
[337. 
IfMk'h.,  13."). 


>s  Mich..  208. 
head    and    ziiu- 

LiRnetite,  169. 
K.  J.,  iron  on  s. 

.T..  Zinc 251 -2h. 

jliinonites,  !'•* 
linionites,  102 
Inagnetite,  17t> 


French  Creek  mines.  Penn.,  179. 

Friedensville  zinc  mines,  Penn.,  250. 

Frisco,  Utah,  27(i. 

Fiitz  I.sland  mine,  Penn.,  179. 

Frost  Drift,  N.  C. .  377. 

Fuc'iis,  E. ,  on  useful  minerals,  461. 

Fi.nter's  Bay  Alaska,  gold,  392. 

G. 

Gagnon  mine,  Butte,  ]Mont..  201. 
Galena     (town),   S.    D.,     lead-silver 

mines.  272. 
Galvanic  action  in  veins,  52. 
Gangue,  defined,  .').">. 

Minerals.  33. 
Gap  mine,  Penn.,  62.  65. 

Nickel  ore,  429. 

Pyrite  ore,  1.S4. 
Gasconade  .sjindstone.  Mo.,  122. 
Galling  arsenic  mine,  Ont.,  412. 
Gay  Head.  Mass.,  liU». 
Gene.see  antimony  mine,  Nev. ,  411. 
Genesee  stage,  5. 

Gentli,  F.  A.;  onBoulderCo.,Colo.,306. 
Geological  classitication,  4. 
Geology,  genei'al  principles,  3. 
Georgetown.  Colo.,  306. 
Georgia,  bauxite.  404,  408. 

Clinton  ore.  114,  117. 

Gold  ore.  379. 

Linionite.   103. 

Manganese.  IIH,  420. 
Georgian  sfcige,  4. 
Geyser  mine,  Colo..  30. 
Giants  Kange,  Minn.,  151. 
(iibl)onsville.  Idaho,  324. 
Gila  Kiver,  N.  M.,   Aluminum   depo- 
sits. 407. 
Gilbert.  G.  K.,  on  faults,  18. 
Giliiiii  Co.,  Colo..  47,  305,  306. 

Co|»|>er  ores,  203. 
Glacial  series.  5. 

(ilenariir,  Ireland,  aluminum  ores. 407. 
Glendale,  Mont.,  lead-silver  deposits, 

273.  317. 
(ileim,  \Vm..  analyses  chromite,  414. 
Globe  district,     Ari/..,    copper    ores, 
21s.  219, 

Gold  and  silver  ores,  335. 
Gogel)ic  Kange,  Midi..  09. 

Manganese  ores.  422. 
Golconda.  Nev..  manganese  ore.s,  421. 
Gold,  Alaska,  392. 

Analysis  of  minerals  containing, 
281. 

Chemical   reactions  in  precipita- 
tion. 371. 

Classi  Heat  ion  of  gravels.  361. 

Deposits,  general  e.\am[)les,  280. 

Gravels.  353.  354,  393, 


Gold,  introductory,  280. 

Quartz  veins.  362. 

Statistics.  401. 
Gold  Hill.  Colo..  305. 
Good  Night  stage.  5. 
Gossjin,  defined.  51. 
Gothic  district.  Colo.,  294. 
(louge  defined.  49. 
Graham  Co. .  Ariz.,  336 
(Jram])ian  Mt.,  Utah,  276. 
Grand  Cafion  of  Ariz.,  334. 
Granite  Co.,  Jlont.,  319. 
Granite  I\lt.  mine.  Moat.,  319. 
Grant  Co.,  N.  M.,  silver  and  gold  ores, 

285, 
Grant  Co.,  Ore.,  gold  mines,  348. 
Grant,  U.  S.,  on  Rainy  Lake  district, 

384. 
Grassy  Hill,  Penn.,  175. 
Great  Basin.  445. 

Arizona.  334. 

California,  349. 

Nevada.  337. 

Oregon.  347. 

Utah,  328. 
Great  Fastern  mercury  mine,Cal.,426. 
Great  Falls.  ]\Iont.,  iron  ores,  90,  109. 

Gold  and  silver,  321. 
^reat  Valley.  101.  102. 

California,  445. 
Gi'eat  Western  mercury  mine,  Cal. , 

426. 
Greenbrier  Co.,  W.  Ya.,  hematites,  121. 
Green-eyed  Monster  mine,  Utah,  333. 
(Treenland,  almninum.  403. 
(Jregory  Comjiaiiy.  Mont.,  273. 
Greisen.  defined,  70. 
Gresley.  W.  S.,  on  Mich,  iron  ore,  138. 
(Jriflin,  P.  H.,  on  Canada  bog  ore.  90. 
Grinnn,  J.,  on   scheme  of  claasifica- 

tion,  455. 
Groildeck.  .V.  von.  73. 

On    scheme  of  classification    of 
ore  deposits.  456. 
Groimd water.  27. 
(Juadalcazar.  Mex..  mercury.  424. 
Guadalupe  mercury  mine.  Mex.,  426. 
(Juanaco,  Cliili.  gold.  34. 
Guavmas  cop[)er  mines.  Lower  Cal., 

221. 
(Jucrrero,  Mex.,  hematite,  188. 
Gmu'.ison  Co. .  Cole,  magnetite.  170. 
Gunnison    Region    Colo.,  silver  and 
gold,  294. 

H. 
Hade  of  a  fault,  21. 
Hague,  A..  Comstock  Lode,  340-844. 

Formation  of  magnetites,  174. 

Hamilton,  Nev.,  gold -silver  ores, 

338. 


470 


INDEX. 


Haile  gold  mine,  S.  C. .  380. 
Harzburgite,  489. 
Hall,  J.,  oited,  124. 
Hall's  Valley,  Colo.,  bog  ore,  90. 
Hamburg  zinc  mine,  N.  J.,  252. 
Hamilton,  Nev.,  388. 
Hamilton  series  and  stage.  5. 
Hammondviile,   N.    Y.,    iron   mines, 
l(i2-i(ir,. 

Handcart  Gnlch,  Colo.,  bog  ore,  90. 
Hanging  Kock  iron  region,  Ky. ,  95. 
Hanna,  on  Nortb  Carolina  gold  belt, 

380. 
Hanover,  N.  M.,  zino  ores,  259. 
Harford  Co.,  Md.,  chromite,  414. 
Harney  Peak,  S.  D.,  314. 
Hartman  zinc  mine,  Penn.,  250. 
Hartwell  iron  district,  Wyo..  154. 
Hastings  Co.,  Ontario.  412. 
Hawortli,    E. ,   on   lead  and  zinc  of 

Missonri,  242. 
Hayden's  Survey,  323. 
Hayes,  C.  W..  388. 

On  aluminnni  depo.sit.s,  405. 
Head  ('ent*'r  niine,  Ariz.,  43. 
Hecla  lead-silver  mines,  Mont.,  273. 
Hecla  mines,  Mont.,  317. 
Heim,  cited,  23. 
Helena  Comimny,  ]\Iont. ,  273. 
Helena,  Mont.,  320. 
Hematite,  brown.  87-100. 

Red  and  specidar,  114-159. 
Henrich,  C,  on  copi^r  ores,  Clifton 
district  210. 

Co'ijier  pyrite,  Tennessee,  190. 

Gold  of  New  Mexico.,  280. 
Henry  Co.,  Va.,  magnetite,  l(i9. 
Hemvood.  cited.  55. 
Herder,  von,  on  vein  fillings,  39. 
Hesse,  (iermany.  bog  ore.  !t2. 
Hestniandjo,  Norway,  cbroinite,  413. 
Higbland  Co.,  Ohio.  CliiitoM  ores,  114. 
High  or  deep  gr;ivels,  Ciil.,  354. 
Highwood  Mt,.  Mont.,  315. 
Hillebrand.     W..     on    Geyser    mine 
waters.  300. 

Gold  deposits  of  Cal,  369. 

Vanadium.  30. 
Hili.  li.  v..  Colo.,  gold,  287. 

Concentration   of  gold   in  veins, 
51. 

Iron  ores  of  Wyo. ,  174. 

Mei'cur  mines.  332. 

Replacements,  45. 
Hill.  R.  T.,  Mex.,  iron  ores,  187, 
Hinsdale  Co.,  Colo.,  gold  and   silver, 

287. 
Hitchcock,  E.,  on  limonites,  100.  | 

Hoefer,  H.,  on  faidts,  23. 
HoUister,  cited,  275. 


Homestake  mine,  Colo.,  294. 
Homestake  mines,  S.  D.,  313. 
Honorine  mine,  Utah,  275. 
Horizon,  defined,  0. 
Horn  Silver  mine,  Utah,  276. 
Horses,  formation  of,  48. 
Huancavelica,   Peru,  mercurv   mine, 

424. 
Hubbard,    L.    L.,    on  Mich.,    copper 

ores,  210. 
Tl  udson  Bay,  gold  deposits,  40. 
Hudson  River,  .stage,  4. 
Huitzuco,  Mex.,  inerciu-y  mines,  424 
Humboldt  Co.,  Nev..  antimony.  411. 

(lold  and  silver  deposits,  340. 
Humboldt-Pocahontas    mine,    Colo., 

299. 
Hunt,T.  S.,  on  Canada  magnetites.  172. 
Hiu'onian  ores,  127. 

System,  4. 
Hui\st,  limonite  bank,  Va.,  93. 
Hussak,  cited,  314. 

I. 
Ibapah  range,  Utah,  332. 
Idalio  Basin.  325. 
Idaho  City  mining  belt,  325. 
Idaho  Co.,  Idjiho,  324. 
Idaho,  geology,  323. 

Co]iper,  222. 

Gold.  323. 

Tin,  443. 
Idaho  Springs,  Colo.,  306. 
Iddings,  .1.  P.,  cited,  59. 

Comstock  Lode.  340-344. 
Idria,  Austria,  mercury,  424 
Igneous  rocks,  defined,  6. 

As  sources  of  metallic   ores,  34, 
59-62. 
Illinois  lead  zinc  mines,  233. 
Impregnations,  57. 
Inde])endence,  Colo.,  294,  305. 
India,  aluminum  ores.  41!''. 
International  (leological  Congress,  3, 
InyoCo.,  Cal..  antimony  (le])osits,  410. 

Lead-silver  deposits,  2.9. 
Iowa,  iron  ores.  9H. 
Lead  and  zinc  mines,  233. 
Ireland,  aliuniiumi  ores,  407. 

Bog  ores.  92. 
Iron  Co..    Utah,  antimony  deposits 
(411.) 

Hematites  and  magnetites,  180. 
Irons,  defined,  06. 
Iron  hat,  defined.  51. 
Iron  in  nature,  8(i,  87. 
Iron  Mt.,  Colo.,  170. 
IronMt,  Mont  ,  321, 
Iron  Mt.,  :\!o..  "iO.  71,  1.57. 
Iron  ores.  ;iniilyses.  s."). 

Cuniposition.  N4,  IMC). 


I 
I 

II 


Is; 

Is. 


294. 
.  818. 
575. 

.  276. 

S. 

ereur_v   mine, 

lich.,    copper 

lits,  40. 

■y  mines,  424 
tiiuoiiv,  411. 
t)sits,  ;i40. 
mine,    Colo., 

ngnetites.  172. 
a.,  93. 


335. 


6. 

-344. 

.  424. 

(5. 

illio  ores,  34, 

233. 

4.  305. 
Ki. 

I  Congress,  3, 
deposits,  41U. 
,  279. 

i3. 
,  407. 

ony  deposits 

netites,  180. 


Iron  ores.  Discussion  of,  85-87 

Impurities,  8.5-,M6. 
Iron  ores,  niagnetite,  160-184 
Iron  ore  localities : 

Adirondack  Mountains,  160. 

Alabama,  104. 

Brazil,  175. 

Colorado,  98,  170-174. 

Connecticut,  101 

Cuba.  m\. 

Georgia.  10,3,  117. 

HeK.se.  (iermanv,  93. 

Ireland.  92. 

Kentucky,  95,  107. 

Clinton  oVe.  114. 
^larviiind,  IHJ. 

Massjichusetts,  101 

Mexic'o,  187. 

Michigan,  125-1,50 

Minnesota,  9(i,  150,  174 

Mis-souri,  96,  133. 

Missi.ssippi,  lOi).  ' 

New  Jersey,  101.  160,  173 

New  York,  114,  167. 

North  Caitflina,  104-109,  160 

Nova  Scotia,  120. 

Ohio,  i)G_i  1,-, 

Oregon.  92. 

Penn.sylvania.  93,  104,  113. 

Tennessee,  103,  114 

Vermont,  U)0.  |S4 

Virgini;..  114.  KW 

We.st  Virginia,  107 

Wi.sconsin,  114. 

Wyoming,  171. 
Iron  ore,  pyrite,  184. 

Red  and  specular  liematite,  140- 
Iron  ores  : 

'"^'h""^'""'^"'^"   Huionites,    100- 

Spathic,  113. 

.Statistics,  1«6. 
Imng,  H.  D..  cited,  205. 

Copj)er  ores,  origin,  209. 

■'  FmuliuufMital  coinplex,"  128 

iMiclngan,  ores,  137. 

Peiiokee  district  ores,  139 

l^e|)lacement.s,  44. 
Isle  Royale  mines,  Mich  ,  307 
isochemic  lines,  183 


INDEX. 


471 


114,  121. 


lead  and  zinc  mines, 
uickel  ores,  123, 
lead    and    zinc 


I  Jasi)er  Co. ,  Mo 

241. 
I  Jefferson  Co. ,  N  Y 

440. 
Jefferson   Co.,    Mo. 

mines,  239. 
Jeffersc  11  Co.,  Mont  ,  317 
Jenuey,  VV.  P..  cited,  43." 
<^Told  dejMj.sits,  283. 
Lead  and  zinc  mines  of  the  Mi.ss. 

Valley,  237,  243,  446. 
l^emj  and  zinc  juines  of  Mo.,  230, 


cited     on 


Joachim.sthal,    Bohemia 

water,  .31. 
John  Day  sUige,  5. 
Johnson,  L.  C,  o„  linionites  97 
Joints,  compression,  13,  14 
Jones  copper  mine,  Cal.,  196 
Jophn.^^Mo.,    zinc  and  lead  mines, 

Judith  Mt.,  Mont.,  315 

Juhen,  A.  A.,  on  origin  of  ,nagnelite. 

Juniata  ^district,  Penn.,  Clinton  ore, 

Jurassic  system,  5. 
Jura-Trias  system,  5. 


T., 


J 

on  Penn. 


limonites, 


Jackson,  C. 

104. 

Jackson  stage,  5. 
Jacksonville,  Ala    404 
Jacui)iranga.  Brazil,  iron  ore.  .56  61 

Tn  n^P- ''*^'  x^^^^"'"-  J'«matite,  \m. 
James  River,  Va.,  hematites.  1.54 


Kadiak  Lsland,  Alaska,  gold  ores  3<)2 
Kansas,  lead  and  zinc  niines  ^40  •^■'^• 
Kearney  mines.  N.  Y.,  iron  oms,  125 
'26a     '  ^■'   '«'^^l-«"ver  orS: 

Kemp,^  J.  F.,  on  Iron  Mt.,  Colo.,  ores. 

On  N.  .1.  zinc  de})osits,  257 
unletm.  copper  deposits   19'> 

JKennedy.W.,  on  nodular  ores     r 
I  Kentucky,  Clinton  ore,  114. 
I         Lead  and  zinc  ores,  239 

Linionites,  95,  I07  " 
Kern  Co..  (Jal..  antimony,  410 
Kerr.  \\.  c,  cited,  377. 

On  X.  ( '.  magnetite  ore,  169 

Un  copper  ores,  I!»4 
Keweenawan  sv.stem.  .''   KW! 
Keweenaw  Point,  Mich..  57  '^04 
Keyes  C.  R..onMo.  lead  oi'es  2l'8 
!KmibaIl,    J.    p.,    ,„,     c-hemis  .V  of 
linionites,   112.  - 

On  Cuban  iron  ores,  187 

On  formation  of  iron  ore.s.  111. 

On  hematite,  124. 
On  magnetite,  173. 
King,  C.,  on  Comstock  Lode,  340,  343. 


Vi-Z 


INDEX. 


Kingston.    Canada,     t'orundum    de- 
posits, north  of,  4!>(>. 

Kittitas  Co.,  Wasli.,  gold  placers,  347. 

Klaniatli  Mt.,  Cal.,  Wd. 

Klauseu,  AiLstria,  ('ited,  43,  43. 

Kniglit.  W.  C..  cited.  174. 

On  llartwell  iron  ores,  11)4. 

Knob  of  igneous  rock  defined,  12. 

KnowUon,  citeil  on  Cal.  ileep  gravels, 
35H. 

Koehler,  G..  ou  scheme  of  (classifica- 
tion of  ore  tleposits.  4')3. 

Kongsberg.  Norway,  cited,  7;5. 

Kootenai  Co..  Idaiio,  3*24. 

Kootenay  Lake.  B.  C.,  3!»4. 

^Iwei-Chau,  mercury  deposits,  Asia, 
434. 


Laccolite  defined,  13. 
Lager  defined,  HS. 
Lagorio,  cited  on  ore  dejwsits,  59. 
Laliontan  1.4ike.  Nev. ,  ;!;5T. 
Lake  Chaniplain  in)u  region,  KiO. 
Lake  Co..  Colo..  2!)4. 
Lake  of  the  Woods,  gold  district.  3.S4. 
Lake  Superior,  copjier  deposits,  44(5. 
(io!d  and  silver.  2«;{. 
Iron  dejjosits,  12').  446. 
]\langane.se  ores.  423. 
Lake  Valley,  N.  M.,  285. 
Lancaster  Co..  Penn.,   chromite,  414. 
Lander  Co..   Nev.,  antimony  mines, 
mines.  411. 
(iold  and  silver  mines.  33!». 
Lane  and   llavward   mines.   Alaska, 

:{!t2. 
Lanes  hisnmth  mine.  Conn..  412. 
Lansing,  Iowa,  lead  and  zinc  mines, 

235. 
La  PlatfiCa.  Colo.,  2H7. 
iramie  Co.,  Wj'o. ,  1,54. 
Ijaramie  stage.  5. 
.assens  Peak,  Cal..  34i» 
^ateral  enrichments  of  a  vein,  49. 
.atcral  secretion,  40,  41,  42. 
aunay.  L.  de.  cited,  461. 
aurentian  system.  4. 
.am-.   M.   F. ,  on    occurrence   of  alu- 
minum, 404. 
Law.son,   A.   C.  on  geology  of  Cal., 
35!). 
On  California  granite.  375. 
On  Painy  Lake  gold  region,  3^4. 
Lead  ulone.  226. 
Lea<l  and  zinc.  233. 
Lead  City.  S.  I).,  313. 
Le.id,  i)r()duction  of,  233. 
Lead  series.  226. 
Lead-silver  ores,  200-263. 


Lead  veins  in  gneiss,  226. 
Leadville,  Colo.,  cited,  17,  31,  35,  51. 

Cop|)er  mines,  221. 

I.,ead  silver  mines,  202. 

Silver  ores,  265. 
Le  Conte,  J.,  on  Cal.  gravels,  356. 

On  mercury  (!ei)osits,  Cal.,  427. 

On    .scheme  of    classification  of 
ore  deposits,  450. 
Lee  Hill  mines.  Minn.,  140. 
Leesburg.  Idaho,  324. 
Lehigh  Co.,  Pemi.,  iron  mines,  101, 

169. 
Lendii  Co.,  Idaho,  324. 
Leonard.   A.   (J.,   on  Lansing  mine, 
Iowa,  235. 

On  origin  lead  zinc  of  Mi.ss.  Val 
lev.  237. 
Lesley,  J.  P.,  cited.  120. 

On  Marcel  I  us  stage,  94. 

Ou  Penn.  iron  mines.  178. 
Les(piereux.  on  Cal.  gravels,  355. 
Lewis  Co..  JloMt  .  320. 
Lewiston.  Mont..  323. 
Lihbey  Creek.  :\loi!t..  323. 
Lignitic  stage.  5. 
Limonites.  analysis,  100. 

Iron  ore,  87-100. 
Lincoln  Co..  Nev.,  338. 
Lindgren,    W..    on    Boise   Co.,   golil 
veins.  325. 

On  Cal.  gold  veins  365. 

On  Cal.  gold,  occurrence,  369. 

On  Calico  district.  351. 

On  War  Kagle  claim.  397. 
Little  Aiuiie  mine.  Colo..  295. 
Little  BeltMts.,  Mont.,  321. 
Little  Cottonwood  Canon,  Utah,  274. 
Little  Rock,  Ark.,  aluminum,  406. 
Livingston  Co.,  Ky..  239. 
Llano  Co..  Te.xas.  (H>})|>er  mines,  204. 
Logan  Co..  Kansas,  nickel  ores,  440. 
lyondon  mines,  Teini..  192. 
Lottner  Serlo.  on  schemes  of  classifi- 
cation of  ore  depo.sits.  451. 
I,ouis{iCo..  Va.,  pyrite  mines,  184. 
Lou])  Fork  stage,  5. 
Lovelock  mines,  Nev..  nickel.  440. 
Lovers  Pit.  Mineville.  N.  Y..  85. 
Low.    A.    P..    on    Hudson    Bay  iron 

ores,  154. 
Lowell.  ]\Iass  .  nickel  ores.  430. 
Lower  Helderberg  series.  4. 
Lt)wer  Claiborne  .stage,  5. 
Low  :\Ioor.  Va. ,  zinc  ores.  95.  256. 
Lubeck,  Me.,  lead  mine,  227. 
Lucky  Boy  mine,  Utah,  333. 
Lyman.  B.  S.,  on  linu)Tn"t.e,  94 
Lyndhur.st.  Va.,  manganese,  418. 
Lyon  Co. ,  Nev. ,  340. 


fi. 

17,  21,  35,  51. 

263. 

•avels,  356. 
ts,  Cal,  427. 
issitication  of 

146. 

lu  mines,  101, 

Liansiiig  mine, 

!  of  IMiss.  Val 

). 

(,  94. 
es,  178. 
■avels,  355. 


oise  Co.,   gold 

3(55. 
irenee,  3(')9. 

351 . 
m,  3i»7. 
lo.,  295. 
,  321. 

ion,  Utah.  274. 
ninuni,  406. 
39. 

per  mines,  204. 
ckel  ores,  440. 
192. 

nies  of  olassiti- 
|)()sits,  451. 
:>  mines.  184. 

nickel.  440. 
N.  Y.,  .S5. 
Json    Bay  iron 

ores.  430. 
ies.  4. 
>,  5. 

,res.  95,  256. 
le,  227. 
h,  333. 
)nite.  94 
;anese,  418. 


INDI'JX. 


473 


Lyon  Co.,  Ky.,  05. 

Lyon  Mt.,  N.  Y.,  iron  ores,  162. 

M 


:\Failison  Co.,  Mont.,  316. 

IMagilalenaMt.,  N.  M.,  260. 

Magna  Ciiarta   mine,  Butte,    Mont. 

Magnetite  iron  ore,  56,  60-63, 160-181 

.Vnaly.ses,  183. 

Bed,'*.  16(1. 

Origin  of  deposits,  181. 

Sands.  IHO. 
Maiden,  Mont.,  323. 
Maine,  c'oi);)er  pyrite,  190. 

(iold,  :!,s;5. 

Tin,  444. 
Manganese  (n-e.s,  416.  418. 
Mansfield  ores.  Penn.,  121.     ' 
IMarcellns  stage,  5. 
Margerie  and  Heim,  cited  on  faults, 

M.'iricopa  Co.,  Ariz.,  m~t. 
iMariposa  Co.,  Cal..  ;}();$. 
Markiiamville,  X.  H.,  mangane.se,  422. 
Marmora,  (an.,  ar.senic  mine.s,  412. 

(rold  mines.  401. 
iMarfpiette  district,  129-136. 
3lar(p!ette  range.  (i9. 
Marsliall  :\It.,  Colo.,  306. 
Marsliall  tunnel,   Georgetown,  Colo., 

50. 
Maryland,  chromite,  414. 
Clinton  ore.  116. 
fiold  mine.s,  ;i81. 
Limonite,  102. 
Mary  Co.,  Tenn.,  192. 
jVIarysville,  Mont.,  320. 
Marysville,  Utah,  424. 
Massachusetts,  lead  mines,  227. 

T.inionite,  101. 
Maytiow  er  nn"ne,  .lont.,  317 
Miynard,  (J.  W.,  on  chromite,  416. 
jVlazon  Creek,  III.,  107. 
McCalley,  H  ,  aluminum.  406. 
McConnell.  U.  (;.,  cited,  388. 

On  Trail  Creek  rock  .series,  396 
McCreath.  A.  S.,  cited,  107 

On  slates,  93. 
Meagher  Co.,  Mont.,  320 
Means.  E.  C.,  referred  to,  256. 
Medina  stage,  4 
Menominee  district.  Lake  Superior 

135-139. 
Meramec  hematite  nunes.  Mo    123 
Mercnr  gold  mines,  Utah.  330. 
Jlercury,  occurrence  of,  424 
Merrill,  G.  p.,  cited.  ;{5 
Merritt.  W.  H..  on  Lake  of  the  Woods 
district,  385. 


137. 
175. 
lead  mine,  227. 


Mesa  hi  district,  Minn.,  134. 
Mesiibi  range.  :\Iinn..  I-M. 
Meso/.oic  grouji,  ,">. 
Metamorpliic  r,,cks,  defined,  6. 
Metasouiatic  defined,  32. 
Methods  of  vein  lilliii^r,  ';j9 
Meunier,  on  origin  of  chromium,  413. 
Mexico,  n-oTi  ore,  187. 
Mercury,  424. 
Tin,  444, 
Mexican  mine.  Alaska,  391. 
Miask.  Urals,  aluminum,  403. 
Michigan,  copper,  204 
(lold,  ;i8;{. 
Iron,  125-l,'i(). 
Michigamme  jasi)e'-. 
Middle  Hill,  Penn 
Middletown,  Conn. 
Midway  .stage.  5. 
Milan,  N.  H.,  pyrite  mine,  184, 
Miller,    Prof.,    on     Kingston,     Out. 

aluminum,  409. 
Mine  Hill,  Cal.,  lUs. 
Mine  Hill.  N.  Y..  zinc  mine.  2.V2 
Mme  la  .Motte.  Mo,,  cited.  .58,  69. 
Lead.  22s. 
Nickel.  429,  440. 
Mhieral  Hill,  Colo..  :303. 
Mineville,  N.  Y.,  72,  85. 
i  Mine  waters.  .52. 
Mining  laws.  447. 
Minnesota  copper  mines.  212. 
Iron  ore.  .Mesabi  range,  1.50. 
Limonite,  96. 
Magnetite,  174. 
Miocene  series.  5. 
Mi.ssi,ssi[)pi  Valley.  19.  446. 
Iron  ores.  |0i». 
Lead  and  zinc,  231,  233. 
Missi.ssippian  .series,  5. 
Mis.soula  Co.,  Mont.,  321. 
Missouri,    Cambrian     red    hematite, 

Co])})er,  213. 

Lead  ores  of  southeastern  Mo.. 

228. 
Limonite.  96. 
Red  hematites,  122 
Tin,  445. 
Zinc  and  lead  in  tlie  southwest, 

Moericke.  cited,  34. 

Moliave  Co. .  Ariz. ,  335. 

Moisie,  Can.,  magnetite  .sjmds,  181. 

Monarch  di.strict,  Colo.,  268. 

Monheim,  V.,  on  zinc  ores  of  Stol- 


berg. 


Monocline  defined,  11,  19. 
Mono  Co.,  Cal.,  3.52. 
Monroe,  Conn.,  bismuth,  412. 


A 


474 


INDEX. 


Montiilban  series,  4. 
Montaiiii,  Kf'oloKy  of,  314. 

('((jtper,  '^();i. 

Lead-silver,  27:?. 

Silver  aiul  gold,  314. 

Till,  443. 
Montana  stage,  .^. 
Monte  Cristo  mine.   Wash.,  arsenio, 

412. 
Moore,  P.  N.,  on  iron  ores,  109. 
Morenei,  Ariz.,  copper  district,  215. 
Morozewioz.  J.,  cited  173. 

On   laws  of  separation   of  ores, 
(12,  (i3, 
Mostjuito  range,  Colo. ,  2(»2. 
Mother  Lode  of  California,  363. 
Monnt  Baldy,  Utah,  333. 
IMouiit  Davidson,  Nev.,  340. 
Moinit  Hope,  N.  J.,  107. 
Mount  ^Marshall,  Colo.,  30(5. 
Mount  McCU'llaii,  Colo.,  295. 
]\[ount  rroniethens,  Nev.,  339 
Mount  Shasta,  Cal..  349. 
]\Iule  Pass,  Mt.,  Ariz.,  217. 
Mullica  Hill,  N.  J.,  .S9. 
Munroe,  H.  S.,  cited  71. 

On  linionites,  41. 

On    .scheme    of  classification  of 
ore  deposits,  457. 
Murphee's  Valley,  Ala..  120. 
Murray  nickel  mine,  Out.,  436. 

N 

Nacemiento  copper  mines,  N.  M.,  334. 
Nason,  F.   L.,   on   geology  of  Ring- 
wood  mines,  169. 

On  N.  J.  zinc  deposits,  252,  257. 

On  ;\Io.  iron  ores,  l.")8. 
Neal  district,  Idaho,  323. 
Neck  of  igneous  rock  defined,  12. 
Neihart  mining  district,  Mont.,  320. 
Nelson  Co.,  Va.,  tin  ore,  444. 
Nelson,  B.  C,  gold,  394. 
Neocene  sy.stem,  5. 
Nevada,  antimony  mines,  411. 

(Jeolog}^  of.  337. 

(Jold  and  silver  deposits,  338. 

Mercury,  424. 

Nickel.  440. 
New  Almaden,  Cal. ,  mercury,  425. 
Newberry,  J.  S.,   on  (topper  deposits 
of  N.  M.,  and  Utah,  224. 

On  iron  ore,  120. 

On  lead-silver  deposits.  Utah,  276. 

On  Silver  Reef,  Utah,  333. 

On   schemes  of  classification  of 
ore  deposits,  453. 
Newl)erry,  W.  E. ,  on  Colorado  mines, 
271. 


New  Bnmswick,  N.  J. ,  copjier  mines, 

190. 
New  Caledonia  nickel,  439. 
Newfoundland,  chromite,  41(t. 

C()l)|icr,  190. 
New  llauut.shire,  lead  mines,  237. 

Tin,  444. 
New  Idria  mines,  Cal,,  426. 
New  Jersey,  copj)erores,  223. 

(iold  ores,  3H3. 

Iron  mines.  173. 

Limonite,  101. 

^Magnetite,  160. 

Zin(^  mines,  253, 
New  Jersey,  (ireensand  stage,  5. 
New    Jersey    Zinc    and    Iron    Co.'s 

mines,  252.  254, 
Newman  Hill.  Col.,  24,  47,  50. 

:\lines  of.  33H. 
New  Me.\ico,  aluminum  deposits,  407, 

Copi)er,  224.  334, 

(leology  of,  2,S4. 

Lead-silver.  260. 

Silver  and  gold,  285. 

Zinc  ores,  259, 
New  River,  Va,,  limonite.  103. 
Newton,  Ciil.,  coi)per  ore.  19(5. 
Newton  Co.,  Mo.,  zinc  mines.  240. 
New  York  co])per  mine.  Ariz,,  219. 
New  York.  Clinton  ore.  114,  120. 

Cold  deposits,  3H3, 

Iron  mines  of  the  Highlands.  167. 

Iron  ore  of  Adirondacks,  166, 

Lead  mines.  227, 

Limonite,  101,  105. 
Nev  Co.,  Nev.,  338. 
Nez  Perces  Co.,  Idaho.  324. 
Niagara  series  and  stage.  4. 
Nicholas,    W.,    on    precipitation    of 

gold.  373. 
Nicholson,    F.,    cm    Missouri    copiier 

mines,  214. 
Nickel.  Arkansas.  440. 

Nevada,  440. 

Norway,  431. 

Ores,  table  and  general  remarks, 
428.  429. 

Ores  of  igneoiis  origin,  61,  04. 

Pennsylvania,  439. 
Niobrara  .stage.  5, 

Northampton,  Jlass.,  lead  mines,  327. 
North  Carolina,  aluminum,  407. 

Coiiper,  194, 

Cold,  37(),  380, 

Limonite,  104-109. 

IMagnetite.  100,  174. 

Nickel.  43il, 

Specular  ores,  155. 

Tin,  144, 
Northern  States,  gold  deposits,  381. 


INDEX. 


opper  mines, 

51). 
,  416. 

nes,  337. 

JG. 
233. 


tage,  5. 
Irou    Co.'a 

r,  50. 

leposits,  407. 


.  103. 

19(). 

lies.  340. 
Ariz.,  219. 
14,  120. 

Chlands.  167. 
.'ks,  160. 


4. 
4. 
pitation     of 

)uri    copper 

al  remarks, 
I,  61,  64. 


mines,  337. 
11,  407. 


Northwest  Territory,   gold  deposits, 


475 


436. 


Ariz 


asits,  381. 


Norway,  chroinite.  113. 
Nova  Scotia,  Clinton  ore,  120 

Copiier  pyrite,  100. 

Gold,  307. 

O 

Oat  Hill.  C'll..  mercury  mine, 
Ocean  as  a  source  of  ores,  33  ' 
Ogdensburg.  N.  J.,  2,-)0. 
Ohio,  Clinton  ore,  114,  H.'}. 

Limonite,  0(),  107. 
Okanogan  Co.,  Wash,,  347. 
Old    Dominion    copi)er  mine. 

Old  Sterling  mine.  Mo.,  125. 

Old  Tenii.  mine,  103. 

Oligoceiie  .serie.s.  ."i. 

< 'liver  mine,  Va.,  i.")3. 

Olmstead,  I.,  on  Piurden  mines.  111 

Oneida  Co.,  Tdalio.  3'J7. 

Ontario  arsenic  mine  at  Deloro  413 

Nickel  mine.  436. 
<  )iirario  mine,  ITtah,  339. 
Ontonagon^   cojiper    district,    Mich., 

Ophir  Canon,  Utah,  37.-).  330 
Ophir  silver  mine.  Cal..  3,")3 
Oppel,  von   on  strata  beds,  55 
0(iuirrh  :\lt.  mines,  Utah,  374' 
Orange  Co..  N.  Y.,  zinc  mine.s,  356 
Orchard  gneiss,  l(i2. 
Ore  dejKisits,  classitication.  .■)4. 

Literature  on,  74-79. 
Ore  minerals,  33. 
Oregon,  geolo^ry  of,  347. 
Oold  mines,  348, 
Mercury,  434. 
Organic    matter   as  a   precipitating 
Jigent,  ()8.  •r       f  fe 

Oriskany  .series.  4. 
Orton,  E..  „n  black  band  ore,  108 

On  dolomitization,  32 
Ouachita  uplift,  446. 
Onray  Co.,  Colo,.  387. 
Owyhee  Co,  Idaho,  35,  337 
Ozark  uplift,  122,  155 


Pacific  Ocean,  445. 

Paliranagat  district,  Nev.,  338 
I  aleozoic  group.  4. 
Palo  Duro  stage,  5. 
Panama  manganese,  433 
Paiiamint  di.strict,  Cal,  ,353 
Park  Co..  Colo.,  295. 
Parting  in  a  vein,  defined,  49. 
Passaic  iron  belt,  N.  J.,  167 
Patton  mines.  Ore.,  bog  ore,'  90 


Peale,  A.   C,  on  Montana  gold  de- 
posits, 315. 

Pearce  mine,  Ariz,,  .silver  and  gold. 

33().  " 

Peai-ce.  K..  Colo.,  g„ld,  ;}06,  365 

On  golil  with  pyrite,  373. 
Pec-hin,  K.  C..  cited,  95. 
Peek.skill.  N.  Y.,  aluminum  ores,  410. 

Magnetite,  172,  173 
Penfield.  S,  L.,  cited,  441. 
Penn.sylviinia,  brown  hematites,  93, 

Chroinite,  414. 

Clinton  ore,  116 

(iold,  3N3. 

T.ead  mine.s,  227. 

Limonite,  101,  104. 

IManstield  ore,  131. 

Spathic  ore,  112. 
Pen()kee(Jogel)i(!  district,  iVlich     1.39 
Penrose,  R.  A.  F..  on  Arkansa.s' iron 
ores,  96. 

^'^o,^*'^'"''*^^    Jiiaiiganese    ores, 

On  Colorado  gold  deix)sits.  304 
Pentlandite,  429. 
Percival     on    Connecticut    limonite, 

Permian  series,  5. 

Perry  Co.,  Penn.,  108. 

Peru,  S.  A.,  mercury,  434 

Peters,  cited,  437. 

Phelps  Co.,  Uo.,  iron  ores, 

Phillips,  .[.  A.,  on  scheme  .„  .:.„ 

r.1  MI-  ''','*^'""  "f"  «»■«  'leposits,  454. 
;^luUipsburg,  Mont.,  319. 
Phoeni.x  cop|)er  di.strict.  Mich  ,  208 
l^liosphorus  in  iron  ore,  s.j   iy;j 
Pictou  Co.,   Nova  Scotia,'   iron 

Pierre  stage,  5. 

Pike's  Peak,  Colo..  403 

Pilot  Knob.  .Mo.,  iron  ores   155 

Pima  Co.,  Ariz.,  lead  silver,  279 

Sliver  and  jrojd.  336. 
Pinal  Co.,  Ariz.,  gold  and  silver,  335 
rincbes  m  a  vein,  49. 
Pioche,  Nev.,  338. 
Pirsson    on  geology  of  Little  Rocky 

Mts.,  322. 
Pitch  of  a  fold  defined,  13 
!  Pitkin  di.strict,  Colo,  394. 
Pittsburg  iron  ore  group,  108. 
i^itt.sl)urg  seam,  108. 
Piute  Co.,  Utah,  333. 
Placer  Co.,  Cal,  chromite,  415. 

Magnetite,  171. 
Placers,  59,  70. 

Plateau  region  of  Rockies,  445. 
Platinum,  441. 


133. 
of  dassifi- 


ore. 


"li 


% 


470 


INDEX. 


Plutoro,  Colo  ,  3flft. 

Pleistoct^tin  system,  5. 

riioct'iie  scrit's,  .">, 

I'oint  Oiforil.  Ort'..  348. 

I'udniiiin  loil<>.  Idiiliu.  :i27. 

I'oitiige  Ijike  copper  miues,  Mich., 

207. 
Portaf^o  stiiRe,  5. 
Poll    nil    Port   hiiy.    Newfoundland, 

chroniit*',  4l(i. 
Porter,  J.  H.,  nii  Clinton  ore,  120. 
F'orter,  J.  A.,  on  Colo.  <j;old,  288. 
Portland  mines.  Cripple  Creek,  Colo., 

Posepny,  F.,  cited,  47,  .17(5. 

On  contact  deposits,  07. 

On  ore  ori;^in.  4")J). 

On  replacement,  44. 
Potrillos,  Me\.,  tin  ores,  444. 
Potoniatr  formation,  5. 
Potsdam  stafi;e,  4. 
Power,  F.  !).,  on  (^lassilication  of  ore 

deposits,  .")(>,  401. 
Pratt,  J.  11.,  on  chromite,  01. 

On  North  (Carolina  chromite,  413. 

On  origin  corundum,  408. 
Prescott,  Ariz.,  2-^(). 
Prime,  F.  .on  Siluro-Cambrian  limon- 
ites.  04,  104. 

On  classitication  of  ore  deposits, 
4.-)l. 
Prometheus  Mt.,  Nev.,  339. 
Prosser  mines,  Ore.,  hog  ore,  91. 
Psilomelane,  410. 
Piierco  stage,  .'). 
Pngel  Sound,  90. 
Puget  Somid  Basin,  Wash.,  340. 
Pumpeliy,  R. ,  on  classitication  of  ore 
depo.sits,  4.")0. 

On  copi)er  rock  of  Michigan,  209. 

On  hematite,  122. 

On  replacements,  44. 
Putnam,  B.  W.,  cited,  73. 

On  magnetite  ore,  105. 
Putnam  Co.,  N.  Y.,  irou  mines,  166. 
Pyrite  beds,  184. 

With  cojiper,  189. 
Pvrrhotite,  of  igneous  origin,  61,  64, 
O."). 

With  nickel,  430. 
Pyrolusite,  410. 


Quaco  Head,  N.  B.,  manganese,  422. 
Quacpiaversal,  defined,  12. 
Quartzlmrgti  rimes  Pass  belt,  32.5. 
Quaternary  system,  Ti. 
Queen  of  the  West  mine,  Colo.,  260. 
Quicksilver,  424. 


Qnigley.  Mont.,  321. 
QuirK-y  mines,  Mich.,  208. 
Quinne.sec  mines,  Mich.,  138. 
Quebec,  chromite,  410. 
tJoi)per  mines,  190, 


Kaihl,  .Vustria,  lead  silver  deposits,  44. 

Rainl)o\v  lo(h',  Mont.,  319. 

Rainier  Mt.,  3 JO. 

Rainy  River  gold  district,  Minn.,  383. 

Rampart  Series  in  .Alaska,  388. 

Ramsliorn  mii,e.  Idaho,  .324. 

Randsburg  gold  mines,  Cal.,  351. 

Raritan  stage,  .1. 

Itathgeb  mine,  Cal.,  870, 

Ravalli  Co.,  Mont.,  321. 

Raven  Mill,  Colo.,  .lO.'i. 

RaynuHid  &  Fly  mine,  Nev.,  338, 

Recent  series,  .'). 

Red  Cliff.  Colo.,  294. 

Red  Mt  ,  .Ma.,  117. 

Red  Mt.,  Kern  Co.,  Cal,  3.52, 

Red  Mt..  Ouray  Co,,  Colo.,  273. 

Red  Ro(!k,  San  Franci.sco,  manganese, 

421. 
Reese  River  district,    Nev,,    banded 
veins.  47. 

Gold  and  .silver,  339. 
Reich,  on  ele(!trical  action  in  veins,  52. 
Replacement,  32,  44,  .58. 
Republic  mine.  Mich.,  8.5. 
Residual  clay  in  a  \ein,  49. 
Residual  i      osits,  .59,  71. 
Rhode  Islauu,  gold  de])osits,  .38,3. 
Richmond,  Mass.,  limonites,  101. 
Rii'hthofen,   von,  on  California  gold 
veins,  30r). 

On  origin  Comstock  lode.  340-341. 
Rickard.T.  ,V,,  on  Califorinagold,  370. 

On  Newman  Hill,  Colo.,  292, 
Rico,  Colo.,  lead-silver.  271. 
Riddle's,  Oregon,  nicrkel,  438, 
Rifting  in  granite,  13,  1-5. 
Rio  (irandc  Co.,  Colo.,  2!),5. 
Rio  Tinto.  Spain,  old  tiinbers,  .52. 
Rio  Viento  Frio,  S.   A.,   manganese, 

423. 
Ripley  stage.  .5. 
River  gravels  witli  gold,  3.53. 
Roanoke,  Va  ,  zinc  ores.  249. 
Roaring  York  Creek,  Colo.,  208. 
R(    .M-t  F.  I-ee  mine,  Colo.,  263. 
A,    oin.son  mine,  Colo.,  200. 
Rochester,  Mont.,  317. 
Rockbridge  Co.,  Va.,  tin  ores,  444. 
Rock  (^rcfdv  district,  Idaho,  325. 
Rocks,  classifie<l,  0. 

Erui)tive,  447. 

Magmas,  00-07. 


INDEX. 


477 


38. 


ileposits,  44. 

Minn.,  383. 

,  388. 

24. 

al,  351. 


ev.,  338, 


353. 
).,  273. 
,  inmganese, 

lev.,    banded 


n  in  veins,  53. 

^). 
49. 

[sits,  383. 
ites,  101. 
Iilirornhi  Rold 

[lode,  340-341. 
•Ilia  gold,  370. 
lolo.,  292, 
k';i. 
-i:!8. 

ibers,  52. 
I,  iiiangauese, 


353. 
l.  249. 
|lo.,3(;8. 
Ilo.,  263. 
1(10. 

Ii  ores,  444. 
Iiho,  325. 


Rofky  Mts.,  faults  of,  "20. 

'.I'ad  and  zinc  di'iiosits,  249. 

SiIvtM' and  gold  dt'|)osits,  308. 
HoKt'fs,  H.  I).,  i-itcd,  120. 

Oil  New  Jersey  zinc  deitfwits,  251. 
liolker,  ('.  .M.,  on  Silver   Heef  ores, 

334. 
IJopes  j::old  mine.  Mich..  383. 
Roscnhusch,  !'.,  cited,  59. 
Kosita.  Colo.,  29(i. 
Hossland.  M.  ('.,  02.  390. 
Ifotli,  J.,  on  an.il yscs  ij.^neous  rocks, 87. 
K'othwcll,  K.  1'.,  on  Silver  l{eef  ore.s, 

:i33. 
Kotten  limestone  stage.  5. 
Howhidou.K  sandstone,  Mo..  133. 
Kouti-ara,     Sweden,     magnetite,    6, 

172,  17.-.. 
Ko.xhury,  ("onn.,  liinonite,  113. 
Huhy  mine,  Colo.,  :'>17. 
Hussell.  1.  C.,  on  Clinton  ore,  120. 
Kussia,  platinum.  441. 
Kye,  N.  Y.,  bog  ore,  91. 


Sacr.amento  Valley,  Cal..  349. 
Satl'onl.  .1.  S.,  on  siliceous  group,  96. 

On  Tennessee  limonites,  103. 
Saguache  Co..  Colo..  29:{. 
Sain  Alto,  .Mex..  tin.  444. 
Salina  Co.,  Ark.,  nickel  ore,  440. 
Salina  series,  4. 

.Salisburv,  ("onn,,  limonites,  101. 
Salt  Co.."Ut.ih.  329. 
San  Benito  Co,,  '.'al.,  antimony,  410, 
San   Hernanlino  Co,,  Cal,  iron  ore. 

171. 
Sandherger.     P..    on    derivation    of 

ores,  :'.J,  41. 
On  dark  silicates,  447. 
San  Diego  Co.,  Cal..  iron  ores,  171. 
San  Emigdio.  Cal.,  antimony,  410, 
Sangn^  de  Cristo  Range,  Colo.,  260- 

:!(Ht. 
San   Joacjuin   Co.,    Cal.,    maug.inese, 

421. 
San  .luan  Mt.,  287. 
San  .hum  Co..  Colo.,  bismuth,  413. 

Oold  and  silver,  2H7. 
San  Luis  Obispo  Co.,  Cal.,  chromite, 

41.\ 
San  Miguel  Co..  Colo.,  290. 
Sante  FeCo.,  N.  M.,  2S('). 
Santa  Rita  coj.per  district,  N,  M.,  319. 
Santa  Hita:\lt.,  N.  M..  2.S5. 
Santiago.  Cuba,  iron  ores,  186,  187. 
Saucon  Valley,  Penn.,  zinc  "'ues,  58, 

2.-)0. 
Sawatch  ^It,  Colo.,  263. 
Schapbach,  cited,  42. 


Schemes  of  classiflcntion  of  deposits, 

44H-457. 
Schmidt,  A.,  on  Missouri   iroti  'ores, 

122.  l.*»H. 
On  Missouri  lead  and  zinc  ores, 

242,  246. 
On  replacement,  44. 
Schranf,    A.,   on    men'ury  deposits, 

425. 
Schoharie  stage,  5. 
Schuyler  copjK'r  mines,  N,  J.,  223. 
Secondary  alteration  in  veins,  50. 
Sedimentary  rocks  delined,  6. 
Segregation,  .59,  72. 
Selvage  in  a  vein  defined,  49. 
Servia,  m(>rcurv,  424. 
Seven  Devils'  (iistrict,  Td:dio,  223. 
Sevier  Co.,  Ark.,  antimony,  411, 
Shaler,    N.  S,,  on  origin  of  Clinton 

ore,   120. 
Shasta  Co.,  Cal.,  chromite,  415. 
Shasta  Mt.,  Cal.,  349. 
Shasta  stage,  5. 
Shaw  mine.  Cal.,  369. 
Shaw  :Mt.  district,  Idaho,  325. 
Shear  zones  delined,  17    W. 
Sheep  Creek  Basin,  Alaska,  393. 
Sheei»  :\lt.  district,  Idaho,  324. 
Sheerer,  cited,  430, 
Sheet  detineil,  12. 
Shepherd  Mt..  Ma.  157. 
Sherbrooke,  Quebec.  190. 
Siderite,  geneti(!  relations,  113. 

Spathic  ore,  106-113. 
Sierra  Co.,  Cal.,  iron  ore,  171. 
Sierra   de   JMercado,   Mex.,  hematite, 

ISH. 
Sierra  Nevada  Range,   Cal.,  geologv 

of,  ;!I9.  :!.5S. 
Siluro Cambrian  limonites,  100-10,5. 
Silver  jind  gold  ores,  analyses,  281. 
])ei)osits.  2S0, 
Statistics,  401. 
Silver  Bow  Basin,  Alaska,  391. 
Silver  Bow  Co.,  :\loTit..  31,S. 
Silver  Bow  Creek,  Mout.,  197,  319. 
Silver,  (California,  3."il. 
Silver  Citv.  X.  M.  407. 
Silver  Cliff,  Colo,.  .57,  296. 
Silver  Islet,  42.  283. 
.Silver  King  mine.  Ariz.,  385. 
Silver  minerals.  2.S1. 
Silver  Plume.  Colo..  306. 
Silver  Reef.  I'tah,  333, 
Silverton,  Colo..  293. 
Silver,  W;ishin<,'ton,  347. 
Simmon's  iron  mines,  ;\Io..  133. 
Simundi,  It.,  on  gokl  ores,  35. 
Sitka.  Alaska,  392. 
Slickensiiles  or  slips  defined,  33. 


478 


IXDKX. 


81(M-iin  Kold  (liHtrict,  B.  C,  !}n4. 
Smillilit'lil  iron  iniiio,  Colo.,  170. 
Hiiiith,  K.  <'..  on  Bliurk  IUIIh  K»ld  de- 
posits. !JI!J. 
Smith,   .J.    P.,   on  auriferou.s  strata. 

H74. 
ShiukkI*''- niino,  Colo.  'iJHl). 
Sinu^if^lcr  !Ml..  Coio, .  'i7(>. 
Sniviiui.  aliiniiiiiiiii,    110. 
8mytli.  ('.  n.,  ,h.,  ou  hematite,  131, 
124,  125. 

Ou  limonites,  113. 
Smyth.  H.  I..,  IHl). 

On    Menomint'o    district    mines, 
lao.  i:!S. 

On  Miclii;?iin  ('oi>per,  210. 

On  >fi('hij;iiii  iron  ore.s,  127,  144. 
Snak.'  River,  hlalio.  27:?,  ;{2!{. 
.Snoiioinisli     Co.,    VVu.sli.,   silver    de- 

])OHits,  iJ47. 
Socorro  Co.,  N.  M.,  gold  and  silver, 

385. 
Sonora,  Mex.,  antimony,  411. 
Soret's  principle,  (il.  171. 
Soinves  of  the  metals.  ;5;',,  34. 
South  Carolina.  Kold  deposits,  380. 
South   Dakota,  gold  aud  silver  ores, 
3()1>. 

Lead  silver,  272. 

Tin.  442. 
Southern  States,  gold,  440. 

I'vrite  under  gold,  184. 
SoutirMt..  Penn.,  iron  ores,  166,  109. 

(Jold  l)elt.  378. 
South  Park.  Colo..  2!).5. 
Spanisii  Peaks,  Colo.,  29,5. 
S])iithic  iron  ore,  1 12. 
SiKMiceville.  Cal.,  <"opper  mine,  19.5. 
Sperry.   F.    L.,   on   Algoma  district, 

441. 
Sperrylite,  438. 
Spurr,  J.  E.,  on  Asjien,  Colo.,  309. 

On  iron  ores,  1.52. 

On  Jlercnr  gold  dejw.sits,  331. 

On  Me.sahi  ores.  152. 

On  Yukon  Basin.  388. 
St.  Frant^ols  Co.,  Mo.,  lead  and  zinc, 

239. 
St.  (ienevieve.  ^lo.,  copper  mines.  313. 
St.  Ltiwrence  Co.,  N.  Y..  lead  mines, 

220. 
St.  Louis,  ;\Io. ,  nickel  ores,  440. 
St.  Mary's  mine,  I'enn.,  179. 
StiUimte,  445. 

Star  distriet.  Utah,  iron  mines,  180. 
Staten  Island  hog  ore.  91. 
Steand)oat  Springs,   Ne^,  30,   35,  44, 
57. 

Mercury  mines,  437. 
Stehekiu  coi)per  district,  Wash.,  223. 


Stein  m.,  Ore..  347. 

Stel/.ner.  A.  W..  cited,  34. 

Step  faults  delined.  24. 

Sterling  Hill  zinc  mine,  N.  J.,  251- 

257. 
Sterling  mines,  Cavuga  Co.,  N.  Y., 

1 1.5. 
Stevens  (Jo.,  Wash.,  gold,  Ml. 
Stevenson.  .1.  J,,  cited,  50. 
StiiMiite,  410. 

Siickeen  river,  .Alaska,  394. 
Stohie  nickel  mine.  Ont.,  430. 
Stokes  Co.,  N.  ('.,  iron  ore.  170. 
Storey  Co..  Nev. .  silver  and  gold,  340. 
Storms,  W.  IL.  on  Alvord  mine,  Cal., 

370. 
Stratum  delined,  0. 
Stral  igraphy  of  auriferous  strata,  374. 
Stream  tin,  413. 
Strike  faidts,  21,  25. 
Suh  carhoniferous  .series.  5, 
Succession  of  minerals  in  an  igneous 

HK-k,  33,  34. 
Sudhurv.  Ont..  Can.,  08. 
Cohalt.  438. 
Iron.  184. 
N'ickel.  429,  431. 
Sullivan   Co..    N.   Y.,    lead   deposits, 

228. 
Sidpliiu-  Bank.  Cal..  menrury,  44,  427. 
Suli)hur  in  iron  ores.  8.5,  80. 
Sulpiuu'  in  rocks.  37. 
Sumdum  Bav,  Alaska,  gold  deposits, 

392. 
Summit  Co.,  Colo.,  394. 

Lead  silver.  21(0. 
Summit  Co..  Utah,  lead-silver,  375. 
Summit  district.  Colo.,  45,  ,52. 
Sunri.s(>  coi)per  mines.  Wyo.,  333. 
S\ve(l(Mi,  lake  ores.  92. 
Sweden,  magnetites,  175. 
Sweet  (Jrass  I  lilts  Mont..  323. 
Sweetwater  Co.,  Wyo.,  308. 
Swells  in  a  vein,  49. 
Syncline  delined,  11,  17. 


Taherg,  Sweden,  iron  ore.  60,  175. 
Taku  mines,  Alaska,  392. 
Talah  Co..  Idalio,  324. 
Tamarack  copper  nnne,  Mich.,  208. 
Tarr,  H.  S.,  ou  Cape  Ann  granite,  13, 
14. 
On  clas,sification  of  ore  deposits, 
4.5!). 
Telegraph  lead  silver  mine,  Utah,  375. 
Teller  Co..  Colo..  300. 
Telluride,  Colo..  288. 
Telhaides  in  gold  ipiartz,  363. 
Tcmescal  tin  mine,  Cal.,  443. 


k 

N.  J.,  251- 

Co.,  N.  Y., 

,  iJ47. 
J. 

>l. 

p,  170. 

1(1  f?<)l(l,  340. 

I  mine,  Cul., 

s  strata,  374. 

5. 

1  an  igneous 


id  deposits, 

ury,  44,  437. 
iii. 

id  deposits. 


ilver,  275. 
),  53. 
'■o.,  233. 


323. 

)8. 


CO,  175. 

[ich.,  208. 
granite,  13, 

re  deposits, 

I,  Utah,  375. 


3fi3. 
.43. 


INDEX. 


Tern  Paliuto<li.stri('t,  Nov.,  338 
Ton  inilo  district,  ('olo,.  2(1(1,  2»4 
TonneHson,  CliiiUm  ore,  114  '||(i  ' 
Coppor,  IJM. 
Lt'iid  /iiic,  'Jf|». 
MiMoiiito,  (»(l,  108. 
Miiiiguiifse.  42(t. 
Teni...,ss,M.  ,„i,u.,  J'„ik  Co.,  Tenn.,  103 
loniiy  (  iipe,  Novu  S(!otia,  432. 
Jernic(>  sitIhs,  5. 
Tcrniim  (Iclliied,  (i. 
Teny  i'«.iik,  S.  I).,  311. 
Tcrliiiry  .sy.steiii,  5. 
IVtoii  Co.,  M(»iit.,  321. 
Texas,  copper-  ores,  204,  334. 
liiiiioiiite,  !I7,  !>8. 
IMercurv,  424,  428 
Tin,  444. 
Texas  iiiiiie.  cliromite,  41,5. 
T«}xas,  Pemi.,  iiitrkel  ore,  439 
Tines  flutchiiiH    antimony    mines 
Nev'.,  411.  ' 

Three  Rivers,  gtie.,  bog  ore,  DO. 
Jluhidei  May,  Can..  284. 
Till>  l'().ster"iron  mine,  k.  Y     1(5(5 
Tilt  Cove.  N.  F.,  nickel  ore.  429 
Tin,  coiKiluding  remarks,  445 

l)e|)osits,  (59,  7().  "  i 

Veins.  72. 
Tin  Cup,  Colo.,  294. 
Tiutic  district,  Utah,  copper  mines, 

Lead-.silver  mines,  375 
Tioga  Co  ,  Penn  ,  121. 
Titaniferous  magnetite,  100,  165. 

In  the  Adirondacks,  171. 

In  Canada,  172. 

C'olorado,  171. 

Minnesota,  174. 

New  .Jersey,  173. 

North  Car()iina,  174. 

Norway,  173. 

Sweden,  172. 

Viiginiji,  171. 

Vyvoming,  ]7l. 
Titanium  in  iron  ores,  8,5,  86 

'■'"< d),  M.  A.,  cited,  352 

Tomlisrone,  Ariz.,  43,  336 
Torrington.  Conn.,  nickel  ores,  430 
lower  C.  \V.,on  Butte  copper  ores. 

Tower,  Mich.,  85. 
T()yab6  Kange,  Nev.,  339. 
Trad  (Jreek  di.strict,  B.  C,  394 
Trad  of  a  fault,  23. 
Treadwell  mine,  Alaska,  390. 
Irenton  series  and  stage,  4. 
Triassic  system,  ,5. 
TriggCo.,  Ky.,95. 
Trotter  zmc  mine,  N.  J.,  253. 


479 


gold 


j  Tucson,  Ariz.,  ;{30. 
ITuolunuie  Co.,  i\a_^  ;},(;} 
Turner,     II.     W..     California 

gravtfis,  359. 
Tu.scaIoo.sii  stage,  5. 
Tuscarora  district,  Nev.,  840. 
lyho,  Nov.,  ',Y.\H. 

Tyrrell,  on  Alaska  gold  gravels,  393 
"'^""414'        '  ""  *''"""'"'te  market, 


Ueberroth  zinc  mine,  Penn    S.W 
Uintah  I\lt..  Utah,  325. 
Uinta  .stage,  5. 

ULsterCo.    N.  V.,  lead  deposits,  329 
I.imomte.s,  III. 

United  .States  Antimony  Co.,  Phila  . 
411.  ' 

United  States,  geological  review  of 
the,  8-10. 

Topography  of  the,  7,  8. 

Magnetite  .sjinds,  181. 
Lnited  Verde  c(.p|MM- mine,  Ariz..  230 
Utah,  antimony,  411. 
I  Copper,  224. 

(Jeoiogy,  ;ja8. 

(•old  and  .silver,  339. 

Limonite,  KJU. 

Mercury.  424. 

Silver-bearing  sandstone,  68. 
Utica  stage,  4. 


Vadose  circulation,  27. 
Vanadium  distribution,  30 

''^    Coit.L""  ""l^«"Wer  Co.. 
Van  Dyck.F.  d,  analysis  by,  254 
Van  Hise,  C.  R.,  cited,  4-1. 

On    claasiUcatiou    of    Michigan 

ores,  133.  * 

On  joints,  14. 

On  Manpietto  di.strict,  129. 
On  Penokee  district,  139. 
On  Z(mes  of  fracture,  2,5, 
Van  Wagenen,  T.  F.,  cited,  53 
Veins,  changes  in  tilling,  .00 

Metliods(tf  tilling.  39 
Swells,  49. 

Vermilion  district,  ]\linn.,  134. 

Lake,  iron  mines,  144-146 
Vermont  chromite,  416 

Gold,  383. 

Iron,  1,S4. . 

Lead,  22* 

Liinonite,*100. 

IManganese,  418. 
Vershire,  Vt.,  copper  ore,  184,  190. 


480 


INDEX. 


Verticals  in  gold  mines,  Black  Hills, 

313. 
Vicksburg  stage,  5. 
Victof  inin;is,  ('  )1().,  3H,"i. 
Virginia.  Clintoa  i>re,  114,  IIG. 

Gold  deposits,  IJHl. 

Lead  and  zinc,  247. 

Liiuoiiile  or  i)ro\vu  hematite,  87- 
114. 

Magnetite.  !()!». 

Mangiuiese.  4ts. 
Virginia  I'ity,  Mont..  810. 
Viviiinite  in  hog  ore,  H!), 
Vogelsi»erg,     (lermany,     aluminu>'i, 

4(»:. 
Vogt.  J.  H.  Ti. ,  on  chromite,  413. 

On  ore  deposits,  ()l-(j5. 

On  nickel  ores,  434. 

On  snli>hides  of  ii-on,  185. 
Vuggs  of  a  vein,  48. 

W 

Wabner.  R.,  cited,  55. 
Wadswortb,  M.  E.,  on  iron  ores,  137, 
135. 

On  classitication  of  ores,  458. 

On  copiHT  ores,  Kewt^ennw,  305. 

On  :Manini'tte  district,  128. 

On  origin  of  copper  ores,  311. 
Wahnapitae  Lake  nickel  mines,  Can.. 

43(). 
Walcott,  C.  D.,  on  fossils  of  Montana, 

315. 
Walker,  T.  L..  on  nickel  ore,  437. 
\\  illingford.  Vt..  manganese  ore,  418. 
\Vardn(>r.   Idaiio,   lead  silver     mines, 

374. 
War  Eagle  mine,  B.  C,  397. 
Wasatch  :Mt.,  Mont.,  314. 

Utah,  IH(»,  374. 
Wasatch  .stage,  5. 
W  ishington  ("o..  Mo.,  lead  and  zinc 

mines,  339. 
Washington  copper  aeposits,  383. 

(leologv.  34(i. 

Silver,  347. 
Washoe  Co..   Nev.,  gold  and  silver 

mii;t>s.  340. 
Water,  undergronnd,  2fi-33. 
Waidvon.  Iowa,  limonite,  98. 
Wiiwa  l^ake  gold  deposits,  385. 
Wayne  Co.,  N.  Y.,  Clinton  ore,  115. 
Wiivneiiburg  (roal  seam.  107. 
Web.ster.  N.  C,  nickel,  439. 
Weed.  W.  H.,  <m  co|)j»erde[K)sits  197. 

On  gold  de])osits,  Montana,  315. 

On  .s'liters,  !5s. 

On  \-ein  formation,  38. 
Weissenbach,  von,  cited,  47, 


Weissenbach,    von,    on    scheme    of 

classification  of  ore,  448. 
Wells,  Profi'ssor.  cited.  441. 
W\^ndt.  A.,  mineral  veins,  51. 
Werner,  cited  on  his  epoch,  55. 
Westiiort.  N.  Y.,  magnetite,  172. 
Weston  mine,  N.  V.,  103. 
West   Stockbridge,    Mass.,    limonite, 

101. 
West  Virginia,  Clinton  ore,  114. 

Limonite,  107. 

Red  lieinatite,  131. 
Wet  Mt.  Vallrv,  Colo.,  290. 
Wln-atlield  !..ine,  I'enn.,  179. 
Wiieatlev  leail  mine,  Penn.,  237. 
Wliitc  Oak  gold  ilistrict,  N,  M,,  385. 
White  Pine  Co.,  Nev.,  338. 
Wliite  River  stage.  •"). 
White  Quail  mine,  Colo.,  207. 
Whitney,  .1.  D.,  on  California  grav- 
els. 3.50. 

On  origin  Micliigan  iron  ore,  135. 

On  Missouri  ores,  1.58. 

On  lead  ores.  330-43. 

On  ]\lother  lode,  California,  304. 

On   scheme  of    cla.ssitication   of 
ores,  453. 

On  Seaweed,  08. 
Vv'ickes,  Mont.,  lead  silver  mines,  373. 
Williams,  (i.  H.,  cited,  138. 

On  chromite,  415. 

On  manganese,  430. 
Willis.  B.,  cited,  178. 
Willow  Creek.  Idaho,  325. 
Wiltsee,  E.,  on  Half  Moon  mine,  Nev. 

338. 
Winchell.  H.  V.,  on  Rainy  Lake  dis- 
trict, 384. 
Winchell,  V.  H.,  and  II.  V.,  on  Pen- 

okee  iron  ore.  150. 
Wind  River  stage  5. 
Winslow,  A.,  Missouri   lead  and  zinc 
mines,  230-244. 

On  Tin,  444. 
Winston,  Mont..  319. 
Wisconsin    Clintoii  ore,  114. 

Leail  and  zinc  mines,  08,  333. 
Wiseonsin  Island.  9. 
Woitf,  J.  E.,  (m  Hibernia  magnetite, 
108. 

On  New  Jersey  zinc  deposits,  3.52. 
Woodman,  J.    E. ,  Nova  Scotia  gold, 

3!({». 
Wood  River  mines.  Idaho,  lead-silver, 

273,  327. 
Woods  mine,  chromite,  414. 
\Vo<i(i\korth,  .1.  H.,  on  Joints.  15, 
Worthington  nickel  mine,  430. 
Wyoming,  coj'per  mines  333. 

(ieology  of,  308. 


scheme    of 

re,  448. 

44t. 

IS,  51. 

)ch,  00. 

■tite,  173. 
> 

w. ,    limonite, 
i)re,  114. 


2m. 
,  179. 
■iin.,  227. 
,  N,  M.,  285. 
J38. 

i.,  267. 
iiforiiia  grav- 

iron  ore,  135. 

■)8. 

lifornia,  364. 
Lssilication   of 


er  mines,  273. 

138. 


ion  mine,  Nev. 
liny  Lake  dis- 

I.  v.,  on  Pen- 

0. 

lead  and  zinc 


,114. 

es,  68,  233. 

lia  magnetite, 

c  deposits,  2.52. 
a  Scotia  gold, 

iho,  lead-silver, 

,  414. 

joints.  15. 
ine,  436. 
es,  223. 


INDEX. 


^V  yoming  iron  mines,  171 

Tm  ores,  443. 
Wythe  Co.,  Va.,  zinc,  247,  348 


481 


YofkP  ^M-  l,^^"^-  'il»n""um,  410 
York  Co 'P-^"'^"*""^"^'  411. 
Vni^    n'  ■^'^""•'  "-on  ores,  101,  179 
Jukon  Basin.  Alaska,  393.         '       ' 
Yukon  silts,  389. 
Yuma  Co.,  Ariz.,  335-337 


Yak  River,  Mont. ,  332 
Yakinia^Co.,    Wash.,   placer  mines, 

Yakutat^Bay.    Alaska,    gold    sands,  | Zirc  minerals,  2.5(f 

Yavai^^Co,.  Ariz.,  gold,  silver  ores,  I         ISfe  S 

Yellow  Jacket  mine.s,  Idaho,  324.         ,  ^'"of  ox?dte?or"e?K?'^'  ''• 


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